Articles | Volume 32, issue 6
https://doi.org/10.5194/angeo-32-651-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/angeo-32-651-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Regular paper
| 
17 Jun 2014
Regular paper |
| 17 Jun 2014
Mirror mode structures near Venus and Comet P/Halley
D. Schmid
Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
M. Volwerk
Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
F. Plaschke
Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
T. L. Zhang
Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
University of Science and Technology of China, Hefei, China
W. Baumjohann
Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
Y. Narita
Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
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Freshly created ions in solar wind start gyrating around the interplanetary magnetic field. When they cross the bow shock, they get an extra kick, and this increases the plasma pressure against the magnetic pressure. This leads to the creation of so-called mirror modes, regions where the magnetic field decreases in strength and the plasma density increases. These structures help in exploring how energy is transferred from the ions to the magnetic field and where around Venus this is happening.
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Mirror modes are magnetic bottles found in the space plasma environment of planets contributing to the energy exchange with the solar wind. We use magnetic field measurements from the NASA Mars Atmosphere and Volatile EvolutioN mission to detect them around Mars and show how they evolve in time and space. The structures concentrate in two regions: one behind the bow shock and the other closer to the planet. They compete with other wave modes depending on the solar flux and heliocentric distance.
Yasuhito Narita, Simon Toepfer, and Daniel Schmid
Ann. Geophys., 41, 87–91, https://doi.org/10.5194/angeo-41-87-2023, https://doi.org/10.5194/angeo-41-87-2023, 2023
Short summary
Short summary
Magnetopause is a shielding boundary of planetary magnetic field. Many mathematical models have been proposed to describe or to reproduce the magnetopause location, but they are restricted to the real-number functions. In this work, we analytically develop a magnetopause model in the complex-number domain, which is advantageous in deforming the magnetopause shape in a conformal (angle-preserving) way, and is suited to compare different models or map one model onto another.
Daniel Schmid and Yasuhito Narita
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2022-30, https://doi.org/10.5194/angeo-2022-30, 2023
Revised manuscript not accepted
Short summary
Short summary
Here we present a useful tool to diagnose the bow shock condition around planets on basis of magnetic field observations. From the upstream and downstream shock normal angle of the magnetic field, it is possible to approximate the relation between compression ratio, Alfvenic Mach number and the solar wind plasma beta. The tool is particularly helpful to study the solar wind conditions and bow shock characteristics during the planetary flybys of the ongoing BepiColombo mission.
Simon Toepfer, Ida Oertel, Vanita Schiron, Yasuhito Narita, Karl-Heinz Glassmeier, Daniel Heyner, Patrick Kolhey, and Uwe Motschmann
Ann. Geophys., 40, 91–105, https://doi.org/10.5194/angeo-40-91-2022, https://doi.org/10.5194/angeo-40-91-2022, 2022
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Revealing the nature of Mercury’s internal magnetic field is one of the primary goals of the BepiColombo mission. Besides the parametrization of the magnetic field contributions, the application of a robust inversion method is of major importance. The present work provides an overview of the most commonly used inversion methods and shows that Capon’s method as well as the Tikhonov regularization enable a high-precision determination of Mercury’s internal magnetic field up to the fifth degree.
Martin Volwerk, Beatriz Sánchez-Cano, Daniel Heyner, Sae Aizawa, Nicolas André, Ali Varsani, Johannes Mieth, Stefano Orsini, Wolfgang Baumjohann, David Fischer, Yoshifumi Futaana, Richard Harrison, Harald Jeszenszky, Iwai Kazumasa, Gunter Laky, Herbert Lichtenegger, Anna Milillo, Yoshizumi Miyoshi, Rumi Nakamura, Ferdinand Plaschke, Ingo Richter, Sebastián Rojas Mata, Yoshifumi Saito, Daniel Schmid, Daikou Shiota, and Cyril Simon Wedlund
Ann. Geophys., 39, 811–831, https://doi.org/10.5194/angeo-39-811-2021, https://doi.org/10.5194/angeo-39-811-2021, 2021
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On 15 October 2020, BepiColombo used Venus as a gravity assist to change its orbit to reach Mercury in late 2021. During this passage of Venus, the spacecraft entered into Venus's magnetotail at a distance of 70 Venus radii from the planet. We have studied the magnetic field and plasma data and find that Venus's magnetotail is highly active. This is caused by strong activity in the solar wind, where just before the flyby a coronal mass ejection interacted with the magnetophere of Venus.
Yasuhito Narita
Ann. Geophys., 39, 759–768, https://doi.org/10.5194/angeo-39-759-2021, https://doi.org/10.5194/angeo-39-759-2021, 2021
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The concept of electromotive force appears in various electromagnetic applications in geophysical and astrophysical fluid studies. The electromotive force is being recognized as a useful tool to construct a more complete picture of turbulent space plasma and has the potential to test for the fundamental processes of dynamo mechanism in space.
Xiaowen Hu, Guoqiang Wang, Zonghao Pan, and Tielong Zhang
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2021-46, https://doi.org/10.5194/angeo-2021-46, 2021
Preprint withdrawn
Short summary
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We develop an automatic procedure based on the two criteria of the Wang-Pan method, and it consists of three parts: selection of the potentially high Alfvénic fluctuation events, evaluation of the OOLs, and determination of the zero offset. We test our automatic procedure by using three months of the partially calibrated data measured by VEX FGM, and find that our automatic procedure is successful to achieve as good results as the Davis-Smith method.
Geng Wang, Mingyu Wu, Guoqiang Wang, Sudong Xiao, Irina Zhelavskaya, Yuri Shprits, Yuanqiang Chen, Zhengyang Zou, Zhonglei Gao, Wen Yi, and Tielong Zhang
Ann. Geophys., 39, 613–625, https://doi.org/10.5194/angeo-39-613-2021, https://doi.org/10.5194/angeo-39-613-2021, 2021
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We investigate the reflection of magnetosonic (MS) waves at the local two-ion cutoff frequency in the outer plasmasphere, which is rarely reported. The observed wave signals demonstrate the reflection at the local two-ion cutoff frequency. From simulations, the waves with small incident angles are more likely to penetrate the thin layer where the group velocity reduces significantly before reflection. These results may help to predict the global distribution of MS waves.
Daniel Schmid, Yasuhito Narita, Ferdinand Plaschke, Martin Volwerk, Rumi Nakamura, and Wolfgang Baumjohann
Ann. Geophys., 39, 563–570, https://doi.org/10.5194/angeo-39-563-2021, https://doi.org/10.5194/angeo-39-563-2021, 2021
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In this work we present the first analytical magnetosheath plasma flow model for the space environment around Mercury. The proposed model is relatively simple to implement and provides the possibility to trace the flow lines inside the Hermean magnetosheath. It can help to determine the the local plasma conditions of a spacecraft in the magnetosheath exclusively on the basis of the upstream solar wind parameters.
Martin Volwerk, David Mautner, Cyril Simon Wedlund, Charlotte Goetz, Ferdinand Plaschke, Tomas Karlsson, Daniel Schmid, Diana Rojas-Castillo, Owen W. Roberts, and Ali Varsani
Ann. Geophys., 39, 239–253, https://doi.org/10.5194/angeo-39-239-2021, https://doi.org/10.5194/angeo-39-239-2021, 2021
Short summary
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The magnetic field in the solar wind is not constant but varies in direction and strength. One of these variations shows a strong local reduction of the magnetic field strength and is called a magnetic hole. These holes are usually an indication that there is, or has been, a temperature difference in the plasma of the solar wind, with the temperature along the magnetic field lower than perpendicular. The MMS spacecraft data have been used to study the characteristics of these holes near Earth.
Horia Comişel, Yasuhito Narita, and Uwe Motschmann
Ann. Geophys., 39, 165–170, https://doi.org/10.5194/angeo-39-165-2021, https://doi.org/10.5194/angeo-39-165-2021, 2021
Short summary
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Identification of a large-amplitude Alfvén wave decaying into a pair of
ion-acoustic and daughter Alfvén waves is one of the major goals in the
observational studies of space plasma nonlinearity.
Growth-rate maps
may serve as a useful tool for predictions of the wavevector spectrum of density
or magnetic field fluctuations in various scenarios for the
wave–wave coupling processes developing at different stages in
space plasma turbulence.
Yasuhito Narita, Ferdinand Plaschke, Werner Magnes, David Fischer, and Daniel Schmid
Geosci. Instrum. Method. Data Syst., 10, 13–24, https://doi.org/10.5194/gi-10-13-2021, https://doi.org/10.5194/gi-10-13-2021, 2021
Short summary
Short summary
The systematic error of calibrated fluxgate magnetometer data is studied for a spinning spacecraft. The major error comes from the offset uncertainty when the ambient magnetic field is low, while the error represents the combination of non-orthogonality, misalignment to spacecraft reference direction, and gain when the ambient field is high. The results are useful in developing future high-precision magnetometers and an error estimate in scientific studies using magnetometer data.
Simon Toepfer, Yasuhito Narita, Daniel Heyner, Patrick Kolhey, and Uwe Motschmann
Geosci. Instrum. Method. Data Syst., 9, 471–481, https://doi.org/10.5194/gi-9-471-2020, https://doi.org/10.5194/gi-9-471-2020, 2020
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The Capon method serves as a powerful and robust data analysis tool when working on various kinds of ill-posed inverse problems. Besides the analysis of waves, the method can be used in a generalized way to compare actual measurements with theoretical models, such as Mercury's magnetic field analysis. In view to the BepiColombo mission this work establishes a mathematical basis for the application of Capon's method to analyze Mercury's internal magnetic field in a robust and manageable way.
Ovidiu Dragoş Constantinescu, Hans-Ulrich Auster, Magda Delva, Olaf Hillenmaier, Werner Magnes, and Ferdinand Plaschke
Geosci. Instrum. Method. Data Syst., 9, 451–469, https://doi.org/10.5194/gi-9-451-2020, https://doi.org/10.5194/gi-9-451-2020, 2020
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We propose a gradiometer-based technique for cleaning multi-sensor magnetic field data acquired on board spacecraft. The technique takes advantage on the fact that the maximum-variance direction of many AC disturbances on board spacecraft does not change over time. We apply the proposed technique to the SOSMAG instrument on board GeoKompsat-2A. We analyse the performance and limitations of the technique and discuss in detail how various disturbances are removed.
Daniel Schmid, Ferdinand Plaschke, Yasuhito Narita, Daniel Heyner, Johannes Z. D. Mieth, Brian J. Anderson, Martin Volwerk, Ayako Matsuoka, and Wolfgang Baumjohann
Ann. Geophys., 38, 823–832, https://doi.org/10.5194/angeo-38-823-2020, https://doi.org/10.5194/angeo-38-823-2020, 2020
Short summary
Short summary
Recently, the two-spacecraft mission BepiColombo was launched to explore Mercury. To measure the magnetic field precisely, in-flight calibration of the magnetometer offset is needed. Usually, the offset is evaluated from magnetic field observations in the solar wind. Since one of the spacecraft will remain within Mercury's magnetic environment, we examine an alternative calibration method. We show that this method is applicable and may be a valuable tool to determine the offset accurately.
Guoqiang Wang, Tielong Zhang, Mingyu Wu, Daniel Schmid, Yufei Hao, and Martin Volwerk
Ann. Geophys., 38, 309–318, https://doi.org/10.5194/angeo-38-309-2020, https://doi.org/10.5194/angeo-38-309-2020, 2020
Short summary
Short summary
Currents are believed to exist in mirror-mode structures and to be self-consistent with the magnetic field depression. Bipolar currents are found in two ion-scale magnetic dips. The bipolar current in a small-size magnetic dip is mainly contributed by electron velocities, which is mainly formed by the magnetic gradient–curvature drift. For another large-size magnetic dip, the bipolar current is mainly caused by an ion bipolar velocity, which can be explained by the ion drift motions.
Ferdinand Plaschke, Maria Jernej, Heli Hietala, and Laura Vuorinen
Ann. Geophys., 38, 287–296, https://doi.org/10.5194/angeo-38-287-2020, https://doi.org/10.5194/angeo-38-287-2020, 2020
Short summary
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Jets of solar-wind plasma commonly hit the Earth's magnetosphere. Using data from the four Magnetospheric Multiscale (MMS) spacecraft, we show statistically that within jets the magnetic field is more aligned with the plasma flow direction than outside of these jets. Our study confirms prior simulation results, but it also shows that the average effect is moderate. The jets' magnetic field is important with respect to their impact on space weather.
Martin Volwerk, Charlotte Goetz, Ferdinand Plaschke, Tomas Karlsson, Daniel Heyner, and Brian Anderson
Ann. Geophys., 38, 51–60, https://doi.org/10.5194/angeo-38-51-2020, https://doi.org/10.5194/angeo-38-51-2020, 2020
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The magnetic field that is carried by the solar wind slowly decreases in strength as it moves further from the Sun. However, there are sometimes localized decreases in the magnetic field strength, called magnetic holes. These are small structures where the magnetic field strength decreases to less than 50 % of the surroundings and the plasma density increases. This paper presents a statistical study of the behaviour of these holes between Mercury and Venus using MESSENGER data.
Ferdinand Plaschke
Geosci. Instrum. Method. Data Syst., 8, 285–291, https://doi.org/10.5194/gi-8-285-2019, https://doi.org/10.5194/gi-8-285-2019, 2019
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Measuring the magnetic field onboard spacecraft requires regular in-flight calibration activities. Among those, determining the output of magnetometers under vanishing ambient magnetic fields, the so-called magnetometer offsets, is essential. Typically, characteristic rotations in solar wind magnetic fields are used to obtain these offsets. This paper addresses the question of how many solar wind data are needed to reach certain accuracy levels in offset determination.
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 37, 971–988, https://doi.org/10.5194/angeo-37-971-2019, https://doi.org/10.5194/angeo-37-971-2019, 2019
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The mirror mode starts as a zero-frequency ion fluid instability and saturates quasi-linearly at very low magnetic level, while forming extended magnetic bubbles. These trap the adiabatically bouncing electron component which forms pairs near the mirror points. The large pair anisotropy causes further growth beyond quasilinear level. Including pressure equilibrium gives and estimate of the required pair density.
Horia Comişel, Yasuhito Narita, and Uwe Motschmann
Ann. Geophys., 37, 835–842, https://doi.org/10.5194/angeo-37-835-2019, https://doi.org/10.5194/angeo-37-835-2019, 2019
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Here we present a scenario that the decay of a field-aligned Alfvén wave can occur simultaneously at various angles to the mean magnetic field, generating a number of second-order fluctuations or waves (after the pump wave as the first-order fluctuation). We refer to the simultaneous decay as
multi-channel couplingsfollowing the notion in scattering theory. Our goal is to study the hypothesis of the multi-channel coupling by running a three-dimensional hybrid plasma simulation.
Yasuhito Narita, Wolfgang Baumjohann, and Rudolf A. Treumann
Ann. Geophys., 37, 825–834, https://doi.org/10.5194/angeo-37-825-2019, https://doi.org/10.5194/angeo-37-825-2019, 2019
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Scaling laws and energy spectra for the electric field, magnetic field, flow velocity, and density are theoretically derived for small-scale turbulence in space plasma on which the electrons behave as a fluid but the ions more as individual particles due to the difference in the mass (the Hall effect). Our theoretical model offers an explanation for the small-scale turbulence spectra measured in near-Earth space.
Laura Vuorinen, Heli Hietala, and Ferdinand Plaschke
Ann. Geophys., 37, 689–697, https://doi.org/10.5194/angeo-37-689-2019, https://doi.org/10.5194/angeo-37-689-2019, 2019
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Before the solar wind encounters the Earth's magnetic field, it is first slowed down and deflected by the Earth's bow shock. We find that downstream of the bow shock regions where the shock normal and the solar wind magnetic field are almost parallel and the shock is more rippled, plasma jets with high earthward velocities are observed significantly more often than elsewhere downstream of the shock. Our results help us forecast the occurrence of these jets and their effects on Earth.
Christoph Lhotka and Yasuhito Narita
Ann. Geophys., 37, 299–314, https://doi.org/10.5194/angeo-37-299-2019, https://doi.org/10.5194/angeo-37-299-2019, 2019
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The interplanetary magnetic field is a consequence of the solar magnetic field and the solar wind. Different magnetic field models exist in literature that allow us to better understand how the solar field extends throughout the solar system. We highlight different aspects of these different interplanetary magnetic field models and discuss possible applications. Verification of these models will become possible using data from the Parker Solar Probe and BepiColombo space mission.
Rudolf A. Treumann, Wolfgang Baumjohann, and Yasuhito Narita
Ann. Geophys., 37, 183–199, https://doi.org/10.5194/angeo-37-183-2019, https://doi.org/10.5194/angeo-37-183-2019, 2019
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Occasional deviations in density and magnetic power spectral densities in an intermediate frequency range are interpreted as an ion-inertial-range response to either the Kolmogorov or Iroshnikov–Kraichnan inertial-range turbulent velocity spectrum.
Ferdinand Plaschke, Hans-Ulrich Auster, David Fischer, Karl-Heinz Fornaçon, Werner Magnes, Ingo Richter, Dragos Constantinescu, and Yasuhito Narita
Geosci. Instrum. Method. Data Syst., 8, 63–76, https://doi.org/10.5194/gi-8-63-2019, https://doi.org/10.5194/gi-8-63-2019, 2019
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Raw output of spacecraft magnetometers has to be converted into meaningful units and coordinate systems before it is usable for scientific applications. This conversion is defined by 12 calibration parameters, 8 of which are more easily determined in flight if the spacecraft is spinning. We present theory and advanced algorithms to determine these eight parameters. They take into account the physical magnetometer and spacecraft behavior, making them superior to previously published algorithms.
Horia Comişel, Yasuhiro Nariyuki, Yasuhito Narita, and Uwe Motschmann
Ann. Geophys., 36, 1647–1655, https://doi.org/10.5194/angeo-36-1647-2018, https://doi.org/10.5194/angeo-36-1647-2018, 2018
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Space plasmas are assumed to be highly active and dynamic systems including waves and turbulence. Electromagnetic waves such as Alfven waves interact with one another, producing daughter waves. In our study based on three-dimensional hybrid simulations, we emphasize the role of obliquely propagating daughter waves in particle heating in low-temperature (or low-beta) plasmas. The evolutions of plasma turbulence, wave dissipation, and heating are essential problems in astrophysics.
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 36, 1563–1576, https://doi.org/10.5194/angeo-36-1563-2018, https://doi.org/10.5194/angeo-36-1563-2018, 2018
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Historical AMPTE-IRM and Equator-S (Eq-S) observations of magnetic mirror modes in the magnetosheath already support the probably coexistence of ion and electron branches on the mirror mode.
Yasuhito Narita and Uwe Motschmann
Ann. Geophys., 36, 1537–1543, https://doi.org/10.5194/angeo-36-1537-2018, https://doi.org/10.5194/angeo-36-1537-2018, 2018
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Venus has no intrinsic magnetic field. On the other hand, we discover that an interplanetary magnetic field may nevertheless penetrate the planetary ionosphere by the diffusion process and reach the planetary surface when the solar wind condition remains for a sufficiently long time, between 12 and 54 h, depending on the condition of ionosphere.
Ching-Chang Cheng, Christopher T. Russell, Ian R. Mann, Eric Donovan, and Wolfgang Baumjohann
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2018-116, https://doi.org/10.5194/angeo-2018-116, 2018
Preprint withdrawn
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The comparison of geomagnetic active and quite events of double substorm onsets responsive to IMF variations shows that the occurrence sequence of all required substorm signatures looks the same and not different for small and large Kp. Double substorm onsets responsive to IMF variations can be characterized with two-stage magnetic dipolarizations in the magnetotail, two auroral breakups of which the first occurring at lower latitudes than the second, and two consecutive Pi2-Ps6 band pulsations.
Minna Palmroth, Heli Hietala, Ferdinand Plaschke, Martin Archer, Tomas Karlsson, Xóchitl Blanco-Cano, David Sibeck, Primož Kajdič, Urs Ganse, Yann Pfau-Kempf, Markus Battarbee, and Lucile Turc
Ann. Geophys., 36, 1171–1182, https://doi.org/10.5194/angeo-36-1171-2018, https://doi.org/10.5194/angeo-36-1171-2018, 2018
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Magnetosheath jets are high-velocity plasma structures that are commonly observed within the Earth's magnetosheath. Previously, they have mainly been investigated with spacecraft observations, which do not allow us to infer their spatial sizes, temporal evolution, or origin. This paper shows for the first time their dimensions, evolution, and origins within a simulation whose dimensions are directly comparable to the Earth's magnetosphere. The results are compared to previous observations.
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 36, 1015–1026, https://doi.org/10.5194/angeo-36-1015-2018, https://doi.org/10.5194/angeo-36-1015-2018, 2018
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The physics of the magnetic mirror mode in its final state of saturation, the thermodynamic equilibrium, is re-examined to demonstrate that the mirror mode is the classical analogue of a superconducting effect in an anisotropic-pressure space plasma. Three different spatial correlation scales are identified which control the behaviour of its evolution into large-amplitude chains of mirror bubbles.
Gurbax S. Lakhina, Bruce T. Tsurutani, George J. Morales, Annick Pouquet, Masahiro Hoshino, Juan Alejandro Valdivia, Yasuhito Narita, and Roger Grimshaw
Nonlin. Processes Geophys., 25, 477–479, https://doi.org/10.5194/npg-25-477-2018, https://doi.org/10.5194/npg-25-477-2018, 2018
Martin Volwerk
Ann. Geophys., 36, 831–839, https://doi.org/10.5194/angeo-36-831-2018, https://doi.org/10.5194/angeo-36-831-2018, 2018
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Using Voyager 1 observations of Jupiter's Io plasma torus, we have determined the location of maximum brightness depending on longitude and the location of Jupiter’s moon Io. We obtain a third viewing direction of the torus (after Voyager 2 and ground observations) and thus two locations, left and right of Jupiter, which are important for the correct modeling of this structure. We also find that a narrow ribbon-like structure only appears when the brightness of the torus exceeds a certain value.
Ferdinand Plaschke and Heli Hietala
Ann. Geophys., 36, 695–703, https://doi.org/10.5194/angeo-36-695-2018, https://doi.org/10.5194/angeo-36-695-2018, 2018
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Fast jets of solar wind particles drive through a slower environment in the magnetosheath, located sunward of the region dominated by the Earth’s magnetic field. THEMIS multi-spacecraft observations show that jets push ambient particles out of their way. These particles flow around the faster jets into the jets’ wake. Thereby, jets stir the magnetosheath, changing the properties of this key region whose particles and magnetic fields can directly interact with the Earth’s magnetic field.
Tomas Karlsson, Ferdinand Plaschke, Heli Hietala, Martin Archer, Xóchitl Blanco-Cano, Primož Kajdič, Per-Arne Lindqvist, Göran Marklund, and Daniel J. Gershman
Ann. Geophys., 36, 655–677, https://doi.org/10.5194/angeo-36-655-2018, https://doi.org/10.5194/angeo-36-655-2018, 2018
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We have studied fast plasma jets outside of Earth’s magnetic environment. Such jets are small-scale structures with a limited lifetime, which may be important in determining the properties of the near-Earth space environment, due to their concentrated kinetic energy. We have used data from the NASA Magnetospheric MultiScale (MMS) satellites to study their properties in detail, to understand how these jets are formed. We have found evidence that there are at least two different types of jets.
Owen W. Roberts, Yasuhito Narita, and C.-Philippe Escoubet
Ann. Geophys., 36, 527–539, https://doi.org/10.5194/angeo-36-527-2018, https://doi.org/10.5194/angeo-36-527-2018, 2018
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In this study we use multi-point spacecraft measurements of magnetic field and electron density derived from spacecraft potential to investigate the three-dimensional structure of solar wind plasma turbulence. We see that there is a dependence on the plasma beta (ratio of thermal to magnetic pressure) as well as a dependence on the type of wind i.e. fast or slow.
Yasuhito Narita and Zoltán Vörös
Ann. Geophys., 36, 101–106, https://doi.org/10.5194/angeo-36-101-2018, https://doi.org/10.5194/angeo-36-101-2018, 2018
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Electromotive force plays a central role in the dynamo mechanism amplifying the magnetic field in turbulent plasmas and electrically conducting fluids. An algorithm is developed to measure the electromotive force using spacecraft data, and it is applied to a magnetic cloud event in interplanetary space. The electromotive force is enhanced when the magnetic cloud passes by the spacecraft, indicating local amplification of the magnetic field.
Owen W. Roberts, Yasuhito Narita, and C.-Philippe Escoubet
Ann. Geophys., 36, 47–52, https://doi.org/10.5194/angeo-36-47-2018, https://doi.org/10.5194/angeo-36-47-2018, 2018
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To investigate compressible plasma turbulence in the solar wind on proton kinetic scales, a high time resolution measurement of the density is obtained from the spacecraft potential. Correlation between the magnetic field strength and the density is investigated as is the rotation sense of the magnetic field. The analysis reveals that compressible fluctuations are characteristic of kinetic Alfvén waves or a mixture of kinetic Alfvén and kinetic slow waves which counter-propagate.
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 35, 1353–1360, https://doi.org/10.5194/angeo-35-1353-2017, https://doi.org/10.5194/angeo-35-1353-2017, 2017
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Poynting's theorem provides a way to determine the spectrum of the dissipation function in magnetic turbulence. It is shown that it includes all contributions of the mechanical part of turbulence. Application to solar wind data identifies the inertial range as a state of self-organization and brings the Taylor hypothesis into question.
Yasuhito Narita and Zoltán Vörös
Nonlin. Processes Geophys., 24, 673–679, https://doi.org/10.5194/npg-24-673-2017, https://doi.org/10.5194/npg-24-673-2017, 2017
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A method is proposed to determine the temporal decay rate of turbulent fluctuations, and is applied to four-point magnetic field data in interplanetary space. The measured decay, interpreted as the energy transfer rate in turbulence, is larger than the theoretical estimate from the fluid turbulence theory. The faster decay represents one of the differences in turbulent processes between fluid and plasma media.
Sudong Xiao, Tielong Zhang, Guoqiang Wang, Martin Volwerk, Yasong Ge, Daniel Schmid, Rumi Nakamura, Wolfgang Baumjohann, and Ferdinand Plaschke
Ann. Geophys., 35, 1015–1022, https://doi.org/10.5194/angeo-35-1015-2017, https://doi.org/10.5194/angeo-35-1015-2017, 2017
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 35, 999–1013, https://doi.org/10.5194/angeo-35-999-2017, https://doi.org/10.5194/angeo-35-999-2017, 2017
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It is suggested that collisionless reconnection under conditions of very strong current-parallel guide fields in dilute plasmas should become a rather efficient source of electromagnetic radiation in the free space modes X and O and their harmonics. The mechanism is based on the electron cyclotron maser instability (ECMI), which can be excited by the anisotropic weakly relativistic electron distribution in the many inertial lengths long electron exhausts caused in reconnection.
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 35, 683–690, https://doi.org/10.5194/angeo-35-683-2017, https://doi.org/10.5194/angeo-35-683-2017, 2017
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We extend the Klimontovich (1967) formulation of kinetic theory of the evolution of the microscopic phase space density to taking into account that the interaction between particles separated from each other at a distance is not instantaneous but requires the transport of information. This is done by reference to the retarded potentials. We derive the fundamental causal Liouville equation for the phase space density of a system composed of a very large number of charged particles.
Yasuhito Narita
Nonlin. Processes Geophys., 24, 203–214, https://doi.org/10.5194/npg-24-203-2017, https://doi.org/10.5194/npg-24-203-2017, 2017
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Various methods in the single-spacecraft data analysis are reviewed to determine physical properties of waves, turbulent fluctuations, and wave-wave and wave-particle interactions in the space plasma environment using the magnetic field, the electric field, and the plasma data.
Yasuhito Narita, Yoshihiro Nishimura, and Tohru Hada
Ann. Geophys., 35, 639–644, https://doi.org/10.5194/angeo-35-639-2017, https://doi.org/10.5194/angeo-35-639-2017, 2017
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An algorithm is proposed to estimate the spectral index of the turbulence energy spectrum directly in the wavenumber domain using multiple-sensor-array data. In contrast to the conventional method using time series data and Fourier transform of the fluctuation energy onto the frequency domain, the proposed algorithm does not require the assumption of Taylor's frozen inflow hypothesis, enabling direct comparison of the spectra in the wavenumber domain with various theoretical predictions.
Yasuhito Narita
Ann. Geophys., 35, 325–331, https://doi.org/10.5194/angeo-35-325-2017, https://doi.org/10.5194/angeo-35-325-2017, 2017
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In situ spacecraft data in space plasma are obtained often as time series data. Using Taylor's frozen-in flow hypothesis, one can interpret the time series data as spatial variations swept by the slow and passing by the spacecraft. A quantitative method for estimating the error for Taylor's hypothesis is developed here.
Dennis Frühauff, Ferdinand Plaschke, and Karl-Heinz Glassmeier
Ann. Geophys., 35, 117–121, https://doi.org/10.5194/angeo-35-117-2017, https://doi.org/10.5194/angeo-35-117-2017, 2017
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Vector magnetic field instruments mounted on spacecraft require precise in-flight calibration of the offsets of all three axes, i.e., the output in vanishing ambient field. While calibration of the spin plane offsets is trivial, we apply a new technique for determining the spin axis offset, not relying on solar wind data but on magnetosheath encounters. This technique is successfully applied to the satellites of the THEMIS mission to update the calibration parameters of the complete mission.
Martin Volwerk, Daniel Schmid, Bruce T. Tsurutani, Magda Delva, Ferdinand Plaschke, Yasuhito Narita, Tielong Zhang, and Karl-Heinz Glassmeier
Ann. Geophys., 34, 1099–1108, https://doi.org/10.5194/angeo-34-1099-2016, https://doi.org/10.5194/angeo-34-1099-2016, 2016
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The behaviour of mirror mode waves in Venus's magnetosheath is investigated for solar minimum and maximum conditions. It is shown that the total observational rate of these waves does not change much; however, the distribution over the magnetosheath is significantly different, as well as the growth and decay of the waves during these different solar activity conditions.
David Fischer, Werner Magnes, Christian Hagen, Ivan Dors, Mark W. Chutter, Jerry Needell, Roy B. Torbert, Olivier Le Contel, Robert J. Strangeway, Gernot Kubin, Aris Valavanoglou, Ferdinand Plaschke, Rumi Nakamura, Laurent Mirioni, Christopher T. Russell, Hannes K. Leinweber, Kenneth R. Bromund, Guan Le, Lawrence Kepko, Brian J. Anderson, James A. Slavin, and Wolfgang Baumjohann
Geosci. Instrum. Method. Data Syst., 5, 521–530, https://doi.org/10.5194/gi-5-521-2016, https://doi.org/10.5194/gi-5-521-2016, 2016
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This paper describes frequency and timing calibration, modeling and data processing and calibration for MMS magnetometers, resulting in a merged search choil and fluxgate data product.
Horia Comişel, Yasuhiro Nariyuki, Yasuhito Narita, and Uwe Motschmann
Ann. Geophys., 34, 975–984, https://doi.org/10.5194/angeo-34-975-2016, https://doi.org/10.5194/angeo-34-975-2016, 2016
Ferdinand Plaschke and Yasuhito Narita
Ann. Geophys., 34, 759–766, https://doi.org/10.5194/angeo-34-759-2016, https://doi.org/10.5194/angeo-34-759-2016, 2016
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Spacecraft-mounted magnetic field instruments (magnetometers) need to be routinely calibrated. This involves determining the magnetometer outputs in vanishing ambient magnetic fields, the so-called offsets. We introduce and test a new method to determine these offsets with high accuracy, the mirror mode method, which is complementary to existing methods. The mirror mode method should be highly beneficial to current and future magnetic field observations near Earth, other planets, and comets.
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 34, 737–738, https://doi.org/10.5194/angeo-34-737-2016, https://doi.org/10.5194/angeo-34-737-2016, 2016
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The rigorous derivation of the Jüttner (covariant Boltzmann) distribution is provided for anisotropic pressure (or temperature) tensors. It was in similar form anticipated first by Gladd (1983). Its manifestly covariant version follows straightforwardly from its scalar property.
Rudolf A. Treumann, Wolfgang Baumjohann, and Yasuhito Narita
Ann. Geophys., 34, 673–689, https://doi.org/10.5194/angeo-34-673-2016, https://doi.org/10.5194/angeo-34-673-2016, 2016
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In support of low-frequency electromagnetic turbulence we formulate the inverse scattering theory of electromagnetic fluctuations in plasma. Its solution provides the turbulent response function which contains all information of the dynamical causes of the electromagnetic fluctuations. This is of basic interest in any electromagnetic turbulence. It requires measurement of magnetic and electric fluctuations but makes no direct use of the turbulent power spectral density.
Ingo Richter, Hans-Ulrich Auster, Gerhard Berghofer, Chris Carr, Emanuele Cupido, Karl-Heinz Fornaçon, Charlotte Goetz, Philip Heinisch, Christoph Koenders, Bernd Stoll, Bruce T. Tsurutani, Claire Vallat, Martin Volwerk, and Karl-Heinz Glassmeier
Ann. Geophys., 34, 609–622, https://doi.org/10.5194/angeo-34-609-2016, https://doi.org/10.5194/angeo-34-609-2016, 2016
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We have analysed the magnetic field measurements performed on the ROSETTA orbiter and the lander PHILAE during PHILAE's descent to comet 67P/Churyumov-Gerasimenko on 12 November 2014. We observed a new type of low-frequency wave with amplitudes of ~ 3 nT, frequencies of 20–50 mHz, wavelengths of ~ 300 km, and propagation velocities of ~ 6 km s−1. The waves are generated in a ~ 100 km region around the comet a show a highly correlated behaviour, which could only be determined by two-point observations.
Y. Narita, H. Comişel, and U. Motschmann
Ann. Geophys., 34, 591–593, https://doi.org/10.5194/angeo-34-591-2016, https://doi.org/10.5194/angeo-34-591-2016, 2016
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys., 34, 557–564, https://doi.org/10.5194/angeo-34-557-2016, https://doi.org/10.5194/angeo-34-557-2016, 2016
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It is demonstrated that the statistical mechanical partition function can be used to construct various different forms of phase space distributions. This indicates that its structure is not restricted to the Gibbs–Boltzmann factor prescription based on counting statistics. Consequences concerning generalised Lorentzians and more general distribution functions are discussed.
Y. Narita, E. Marsch, C. Perschke, K.-H. Glassmeier, U. Motschmann, and H. Comişel
Ann. Geophys., 34, 393–398, https://doi.org/10.5194/angeo-34-393-2016, https://doi.org/10.5194/angeo-34-393-2016, 2016
Sudong Xiao, Tielong Zhang, Yasong Ge, Guoqiang Wang, Wolfgang Baumjohann, and Rumi Nakamura
Ann. Geophys., 34, 303–311, https://doi.org/10.5194/angeo-34-303-2016, https://doi.org/10.5194/angeo-34-303-2016, 2016
Y. Narita, R. Nakamura, W. Baumjohann, K.-H. Glassmeier, U. Motschmann, and H. Comişel
Ann. Geophys., 34, 85–89, https://doi.org/10.5194/angeo-34-85-2016, https://doi.org/10.5194/angeo-34-85-2016, 2016
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Four-spacecraft Cluster observations of turbulent fluctuations in the magnetic reconnection region in the geomagnetic tail show for the first time an indication of ion Bernstein waves, electromagnetic waves that propagate nearly perpendicular to the mean magnetic field and are in resonance with ions. Bernstein waves may influence current sheet dynamics in the reconnection outflow such as a bifurcation of the current sheet.
M. Volwerk, I. Richter, B. Tsurutani, C. Götz, K. Altwegg, T. Broiles, J. Burch, C. Carr, E. Cupido, M. Delva, M. Dósa, N. J. T. Edberg, A. Eriksson, P. Henri, C. Koenders, J.-P. Lebreton, K. E. Mandt, H. Nilsson, A. Opitz, M. Rubin, K. Schwingenschuh, G. Stenberg Wieser, K. Szegö, C. Vallat, X. Vallieres, and K.-H. Glassmeier
Ann. Geophys., 34, 1–15, https://doi.org/10.5194/angeo-34-1-2016, https://doi.org/10.5194/angeo-34-1-2016, 2016
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The solar wind magnetic field drapes around the active nucleus of comet 67P/CG, creating a magnetosphere. The solar wind density increases and with that the pressure, which compresses the magnetosphere, increasing the magnetic field strength near Rosetta. The higher solar wind density also creates more ionization through collisions with the gas from the comet. The new ions are picked-up by the magnetic field and generate mirror-mode waves, creating low-field high-density "bottles" near 67P/CG.
Y. Narita
Ann. Geophys., 33, 1413–1419, https://doi.org/10.5194/angeo-33-1413-2015, https://doi.org/10.5194/angeo-33-1413-2015, 2015
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A lot of efforts have been put into understanding the turbulence structure in space and astrophysical plasmas, in particular how the filamentary structure develops as the length scale of the turbulent fluctuations changes from large to smaller ones. Motivated by the recent spacecraft observations in the solar wind, an analytic model is proposed to explain the nature of filament-formation processes in space plasma turbulence with a successful test against the spacecraft observations.
I. Richter, C. Koenders, H.-U. Auster, D. Frühauff, C. Götz, P. Heinisch, C. Perschke, U. Motschmann, B. Stoll, K. Altwegg, J. Burch, C. Carr, E. Cupido, A. Eriksson, P. Henri, R. Goldstein, J.-P. Lebreton, P. Mokashi, Z. Nemeth, H. Nilsson, M. Rubin, K. Szegö, B. T. Tsurutani, C. Vallat, M. Volwerk, and K.-H. Glassmeier
Ann. Geophys., 33, 1031–1036, https://doi.org/10.5194/angeo-33-1031-2015, https://doi.org/10.5194/angeo-33-1031-2015, 2015
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We present a first report on magnetic field measurements made in the coma of comet 67P/C-G in its low-activity state. The plasma environment is dominated by quasi-coherent, large-amplitude, compressional magnetic field oscillations around 40mHz, differing from the observations at strongly active comets where waves at the cometary ion gyro-frequencies are the main feature. We propose a cross-field current instability associated with the newborn cometary ions as a possible source mechanism.
H. Comişel, Y. Narita, and U. Motschmann
Ann. Geophys., 33, 345–350, https://doi.org/10.5194/angeo-33-345-2015, https://doi.org/10.5194/angeo-33-345-2015, 2015
M. Volwerk, K.-H. Glassmeier, M. Delva, D. Schmid, C. Koenders, I. Richter, and K. Szegö
Ann. Geophys., 32, 1441–1453, https://doi.org/10.5194/angeo-32-1441-2014, https://doi.org/10.5194/angeo-32-1441-2014, 2014
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We discuss three flybys (within an 8-day time span) of comet 1P/Halley by VEGA 1, 2 and Giotto. Looking at two different plasma phenomena: mirror mode waves and field line draping; we study the differences in SW--comet interaction between these three flybys. We find that on this time scale (comparable to Rosetta's orbits) there is a significant difference, both caused by changing outgassing rate of the comet and changes in the solar wind. We discuss implications for Rosetta RPC observations.
H. Comişel, Y. Narita, and U. Motschmann
Nonlin. Processes Geophys., 21, 1075–1083, https://doi.org/10.5194/npg-21-1075-2014, https://doi.org/10.5194/npg-21-1075-2014, 2014
R. A. Treumann and W. Baumjohann
Ann. Geophys., 32, 975–989, https://doi.org/10.5194/angeo-32-975-2014, https://doi.org/10.5194/angeo-32-975-2014, 2014
R. A. Treumann and W. Baumjohann
Ann. Geophys., 32, 643–650, https://doi.org/10.5194/angeo-32-643-2014, https://doi.org/10.5194/angeo-32-643-2014, 2014
M. Wilczek, H. Xu, and Y. Narita
Nonlin. Processes Geophys., 21, 645–649, https://doi.org/10.5194/npg-21-645-2014, https://doi.org/10.5194/npg-21-645-2014, 2014
R. Wang, R. Nakamura, T. Zhang, A. Du, W. Baumjohann, Q. Lu, and A. N. Fazakerley
Ann. Geophys., 32, 239–248, https://doi.org/10.5194/angeo-32-239-2014, https://doi.org/10.5194/angeo-32-239-2014, 2014
H. Aryan, M. A. Balikhin, A. Taktakishvili, and T. L. Zhang
Ann. Geophys., 32, 223–230, https://doi.org/10.5194/angeo-32-223-2014, https://doi.org/10.5194/angeo-32-223-2014, 2014
R. Nakamura, F. Plaschke, R. Teubenbacher, L. Giner, W. Baumjohann, W. Magnes, M. Steller, R. B. Torbert, H. Vaith, M. Chutter, K.-H. Fornaçon, K.-H. Glassmeier, and C. Carr
Geosci. Instrum. Method. Data Syst., 3, 1–11, https://doi.org/10.5194/gi-3-1-2014, https://doi.org/10.5194/gi-3-1-2014, 2014
R. A. Treumann and W. Baumjohann
Nonlin. Processes Geophys., 21, 143–148, https://doi.org/10.5194/npg-21-143-2014, https://doi.org/10.5194/npg-21-143-2014, 2014
Y. Narita
Nonlin. Processes Geophys., 21, 41–47, https://doi.org/10.5194/npg-21-41-2014, https://doi.org/10.5194/npg-21-41-2014, 2014
M. Volwerk, C. Koenders, M. Delva, I. Richter, K. Schwingenschuh, M. S. Bentley, and K.-H. Glassmeier
Ann. Geophys., 31, 2201–2206, https://doi.org/10.5194/angeo-31-2201-2013, https://doi.org/10.5194/angeo-31-2201-2013, 2013
C. Perschke, Y. Narita, S. P. Gary, U. Motschmann, and K.-H. Glassmeier
Ann. Geophys., 31, 1949–1955, https://doi.org/10.5194/angeo-31-1949-2013, https://doi.org/10.5194/angeo-31-1949-2013, 2013
F. Plaschke, H. Hietala, and V. Angelopoulos
Ann. Geophys., 31, 1877–1889, https://doi.org/10.5194/angeo-31-1877-2013, https://doi.org/10.5194/angeo-31-1877-2013, 2013
Y. Narita, R. Nakamura, and W. Baumjohann
Ann. Geophys., 31, 1605–1610, https://doi.org/10.5194/angeo-31-1605-2013, https://doi.org/10.5194/angeo-31-1605-2013, 2013
R. A. Treumann and W. Baumjohann
Ann. Geophys., 31, 1191–1193, https://doi.org/10.5194/angeo-31-1191-2013, https://doi.org/10.5194/angeo-31-1191-2013, 2013
M. Volwerk, N. André, C. S. Arridge, C. M. Jackman, X. Jia, S. E. Milan, A. Radioti, M. F. Vogt, A. P. Walsh, R. Nakamura, A. Masters, and C. Forsyth
Ann. Geophys., 31, 817–833, https://doi.org/10.5194/angeo-31-817-2013, https://doi.org/10.5194/angeo-31-817-2013, 2013
C. Nabert, K.-H. Glassmeier, and F. Plaschke
Ann. Geophys., 31, 419–437, https://doi.org/10.5194/angeo-31-419-2013, https://doi.org/10.5194/angeo-31-419-2013, 2013
M. Volwerk, X. Jia, C. Paranicas, W. S. Kurth, M. G. Kivelson, and K. K. Khurana
Ann. Geophys., 31, 45–59, https://doi.org/10.5194/angeo-31-45-2013, https://doi.org/10.5194/angeo-31-45-2013, 2013
A. Alexandrova, R. Nakamura, V. S. Semenov, I. V. Kubyshkin, S. Apatenkov, E. V. Panov, D. Korovinskiy, H. Biernat, W. Baumjohann, K.-H. Glassmeier, and J. P. McFadden
Ann. Geophys., 30, 1727–1741, https://doi.org/10.5194/angeo-30-1727-2012, https://doi.org/10.5194/angeo-30-1727-2012, 2012
