Articles | Volume 37, issue 3
https://doi.org/10.5194/angeo-37-381-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/angeo-37-381-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
A new scenario applying traffic flow analogy to poleward expansion of auroras
Office Geophysik, Ogoori, Japan
Related authors
Osuke Saka
EGUsphere, https://doi.org/10.5194/egusphere-2025-716, https://doi.org/10.5194/egusphere-2025-716, 2025
This preprint is open for discussion and under review for Annales Geophysicae (ANGEO).
Short summary
Short summary
Negatively charged solitary potential areas (ion holes) are generated in collisional ionosphere by the incident energetic electrons. Those negative potential regions are ionospheric driver of discrete aurora. When the ion hole becomes sheet-like structure (auroral arc), shear flows develop in the sheet to form spirals.
Osuke Saka
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2023-32, https://doi.org/10.5194/angeo-2023-32, 2023
Manuscript not accepted for further review
Short summary
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Auroral spirals known as northern lights are a spectacular light show in the polar night sky. Internal processes in the polar ionosphere initiate northern lights by producing charge separations along the field lines. Parallel electric fields generated above the ionosphere by charge separations are steady-state electric fields. They occasionally discharge to produce northern lights, analogous to lightning flash in a thunderstorm.
Osuke Saka
Ann. Geophys., 41, 369–373, https://doi.org/10.5194/angeo-41-369-2023, https://doi.org/10.5194/angeo-41-369-2023, 2023
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Transverse electric fields transmitted from the magnetosphere and those generated by the neutral winds yield a local breakdown of the charge neutrality at the boundaries between the thermosphere and mesosphere. The breakdown may create parallel electric fields in the thermosphere to produce spiral auroras and outflows. This explanation supposes an auroral generator located not in a distant space, but rather in our much nearer upper atmosphere.
Osuke Saka
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2021-66, https://doi.org/10.5194/angeo-2021-66, 2021
Revised manuscript not accepted
Short summary
Short summary
Auroral spirals known as northern lights are a spectacular light show in the polar night sky. We show that auroral spirals are produced in the polar ionosphere by the internal processes that ensure quasi-neutral equilibrium of the polar ionosphere which is often violated during field line dipolarization. The internal driver produces spiral auroras in a manner different from the field line mapping scenario.
Osuke Saka
Ann. Geophys., 39, 455–460, https://doi.org/10.5194/angeo-39-455-2021, https://doi.org/10.5194/angeo-39-455-2021, 2021
Short summary
Short summary
The ionosphere is a partly ionized medium above the atmosphere. Because of its anisotropic properties, the imposed electric fields from the magnetosphere produce space charge. Polarization electric fields induced in the ionosphere by this process generate ion drifts (Pedersen currents) and plasma evaporation along the field lines, thus achieving a quasi-neutral equilibrium of the ionosphere. The evaporation grows as a large-scale parallel potential structure in the magnetosphere.
Osuke Saka
Ann. Geophys., 38, 467–479, https://doi.org/10.5194/angeo-38-467-2020, https://doi.org/10.5194/angeo-38-467-2020, 2020
Short summary
Short summary
The first 10 min interval of Pi2 onset is the most active period of substorms composed of field line deformations associated with an increase in curvature radius of flux tubes and their longitudinal expansion. The flux tube deformations were triggered by the ballooning instability of slow magnetoacoustic waves upon arrival of the dipolarization front from the tail. They preceded the classical dipolarization caused by the reduction of cross-tail currents and resulting pileup of the field lines.
O. Saka, K. Hayashi, and M. Thomsen
Ann. Geophys., 32, 1011–1023, https://doi.org/10.5194/angeo-32-1011-2014, https://doi.org/10.5194/angeo-32-1011-2014, 2014
Osuke Saka
EGUsphere, https://doi.org/10.5194/egusphere-2025-716, https://doi.org/10.5194/egusphere-2025-716, 2025
This preprint is open for discussion and under review for Annales Geophysicae (ANGEO).
Short summary
Short summary
Negatively charged solitary potential areas (ion holes) are generated in collisional ionosphere by the incident energetic electrons. Those negative potential regions are ionospheric driver of discrete aurora. When the ion hole becomes sheet-like structure (auroral arc), shear flows develop in the sheet to form spirals.
Osuke Saka
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2023-32, https://doi.org/10.5194/angeo-2023-32, 2023
Manuscript not accepted for further review
Short summary
Short summary
Auroral spirals known as northern lights are a spectacular light show in the polar night sky. Internal processes in the polar ionosphere initiate northern lights by producing charge separations along the field lines. Parallel electric fields generated above the ionosphere by charge separations are steady-state electric fields. They occasionally discharge to produce northern lights, analogous to lightning flash in a thunderstorm.
Osuke Saka
Ann. Geophys., 41, 369–373, https://doi.org/10.5194/angeo-41-369-2023, https://doi.org/10.5194/angeo-41-369-2023, 2023
Short summary
Short summary
Transverse electric fields transmitted from the magnetosphere and those generated by the neutral winds yield a local breakdown of the charge neutrality at the boundaries between the thermosphere and mesosphere. The breakdown may create parallel electric fields in the thermosphere to produce spiral auroras and outflows. This explanation supposes an auroral generator located not in a distant space, but rather in our much nearer upper atmosphere.
Osuke Saka
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2021-66, https://doi.org/10.5194/angeo-2021-66, 2021
Revised manuscript not accepted
Short summary
Short summary
Auroral spirals known as northern lights are a spectacular light show in the polar night sky. We show that auroral spirals are produced in the polar ionosphere by the internal processes that ensure quasi-neutral equilibrium of the polar ionosphere which is often violated during field line dipolarization. The internal driver produces spiral auroras in a manner different from the field line mapping scenario.
Osuke Saka
Ann. Geophys., 39, 455–460, https://doi.org/10.5194/angeo-39-455-2021, https://doi.org/10.5194/angeo-39-455-2021, 2021
Short summary
Short summary
The ionosphere is a partly ionized medium above the atmosphere. Because of its anisotropic properties, the imposed electric fields from the magnetosphere produce space charge. Polarization electric fields induced in the ionosphere by this process generate ion drifts (Pedersen currents) and plasma evaporation along the field lines, thus achieving a quasi-neutral equilibrium of the ionosphere. The evaporation grows as a large-scale parallel potential structure in the magnetosphere.
Osuke Saka
Ann. Geophys., 38, 467–479, https://doi.org/10.5194/angeo-38-467-2020, https://doi.org/10.5194/angeo-38-467-2020, 2020
Short summary
Short summary
The first 10 min interval of Pi2 onset is the most active period of substorms composed of field line deformations associated with an increase in curvature radius of flux tubes and their longitudinal expansion. The flux tube deformations were triggered by the ballooning instability of slow magnetoacoustic waves upon arrival of the dipolarization front from the tail. They preceded the classical dipolarization caused by the reduction of cross-tail currents and resulting pileup of the field lines.
O. Saka, K. Hayashi, and M. Thomsen
Ann. Geophys., 32, 1011–1023, https://doi.org/10.5194/angeo-32-1011-2014, https://doi.org/10.5194/angeo-32-1011-2014, 2014
Related subject area
Subject: Magnetosphere & space plasma physics | Keywords: Auroral phenomena
Morphological evolution and spatial profile changes of poleward moving auroral forms
Surveying pulsating auroras
Wavelet analysis of the magnetotail response to solar wind fluctuations during HILDCAA events
Multiscale estimation of the field-aligned current density
Characteristics of the electrojet during intense magnetic disturbances
Differentiating diffuse auroras based on phenomenology
Anton Goertz, Noora Partamies, Daniel Whiter, and Lisa Baddeley
Ann. Geophys., 41, 115–128, https://doi.org/10.5194/angeo-41-115-2023, https://doi.org/10.5194/angeo-41-115-2023, 2023
Short summary
Short summary
Poleward moving auroral forms (PMAFs) are specific types of aurora believed to be the signature of the connection of Earth's magnetic field to that of the sun. In this paper, we discuss the evolution of PMAFs with regard to their auroral morphology as observed in all-sky camera images. We interpret different aspects of this evolution in terms of the connection dynamics between the magnetic fields of Earth and the sun. This sheds more light on the magnetic interaction between the sun and Earth.
Eric Grono and Eric Donovan
Ann. Geophys., 38, 1–8, https://doi.org/10.5194/angeo-38-1-2020, https://doi.org/10.5194/angeo-38-1-2020, 2020
Short summary
Short summary
This is the first survey of pulsating auroras which is differentiated by type. Pulsating auroras are found to be almost always an early-morning phenomenon and are almost entirely lacking persistent structuring before midnight. Long-lived patches which are known to move with convection primarily appear after midnight. These patches are a less common form of pulsating aurora and are found to originate from the inner magnetosphere, in agreement with past observations of their source region.
Adriane Marques de Souza Franco, Ezequiel Echer, and Mauricio José Alves Bolzan
Ann. Geophys., 37, 919–929, https://doi.org/10.5194/angeo-37-919-2019, https://doi.org/10.5194/angeo-37-919-2019, 2019
Short summary
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The wavelet transform was employed in nine HILDCAA events for intervals in which the Cluster crossed the magnetotail in order to identify the most energetic periods of these events in the magnetotail. It was seen that 76 % of the periods identified are ≤4 h. Using the cross wavelet analysis technique between Bz–IMF components and the Bx geomagnetic components, it was identified that the coupling of energy is stronger in periods between 2 and 4 h, which are typical substorm periods.
Costel Bunescu, Joachim Vogt, Octav Marghitu, and Adrian Blagau
Ann. Geophys., 37, 347–373, https://doi.org/10.5194/angeo-37-347-2019, https://doi.org/10.5194/angeo-37-347-2019, 2019
Liudmila I. Gromova, Matthias Förster, Yakov I. Feldstein, and Patricia Ritter
Ann. Geophys., 36, 1361–1391, https://doi.org/10.5194/angeo-36-1361-2018, https://doi.org/10.5194/angeo-36-1361-2018, 2018
Short summary
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Hall current variations in different time sectors during six magnetic storms of the summer seasons in 2003 and 2005 are examined. The sequence of the phenomena, their structure, positions and the strength of the polar and the auroral Hall electrojets were investigated using scalar magnetic field measurements obtained from the CHAMP satellite. We analyzed the correlations and the regression relations of the electrojets with auroral and ring current activity, the IMF, and solar wind parameters.
Eric Grono and Eric Donovan
Ann. Geophys., 36, 891–898, https://doi.org/10.5194/angeo-36-891-2018, https://doi.org/10.5194/angeo-36-891-2018, 2018
Short summary
Short summary
The solar wind reshapes Earth's magnetic field to create our magnetosphere and powers many dynamic processes in our plasma-filled environment, some of which produce the aurora. Networks of ground-based all-sky cameras are valuable tools that offer a large field-of-view with which to study the aurora. Using sequences of auroral images, this study defines criteria for differentiating an important type of aurora whose subcategories are often conflated.
Cited articles
Akasofu, S.-I., Kimball, D. S., and Meng, C.-I.: Dynamics of the aurora-VII,
Equatorward motions and the multiplicity of auroral arcs,
J. Atmos. Terr. Phys., 28, 627–635, 1966.
Angelopoulos, V., McFadden, J. P., Larson, D., Carlson, C. W., Mend, S. B., Frey, H., Phan, T., Sibeck, D. G., Glassmeier, K.-H., Auster, U., Donovan, E., Mann, I. R., Rae, I. J., Russell, C. T., Runov, A., Zhou, X.-Z., and Kepko, L.: Tail reconnection triggering substorm onset,
Science, 321, 931–935, 2008.
Chao, J. K., Kan, J. R., Lui, A. T. Y., and Akasofu, S.-I.: A model for thinning
of the plasma sheet, Planet. Space Sci., 25, 703–710, 1977.
Chen, F. F.: Introduction to plasma physics, Plenum Press, New York, 1974.
Ergun, R. E., Andersson, L., Main, D., Su, Y.-J., Newman, D. L., Goldman, M. V., Carlson, C. W., McPhadden, J. P., and Mozer, F. S.: Parallel electric fields in the upward current region
of the aurora: Numerical solutions, Phys. Plasmas, 9, 3695–3704, 2002.
Haerendel, G.: Plasma drifts in the auroral ionosphere derived from Barium
release, in: Earth magnetospheric processes, edited by: McComac, B. M., D.Reidel
Publishing Company, Dordrecht-Holland, 246–257, 1972.
Haerendel, G.: Substorm onset: Current sheet avalanche and stop layer,
J. Geophys. Res., 120, 1697–1714, https://doi.org/10.1002/2014JA020571, 2015.
Hasegawa, A. and Sato, T.: Existence of a negative potential solitary-wave
structure and formation of a double layer, Phys. Fluids, 25, 632–635, 1982.
Hudson, M. K., Lotko, W., Roth, I., and Witt, E.: Solitary waves and double
layers on auroral field lines, J. Geophys. Res., 88, 916–926, 1983.
Kan, J. R., Longenecker, D. U., and Olson, J. V.: A transient response model of
Pi2 pulsations, J. Geophys. Res., 87, 7483–7488, 1982.
Kelley, M. C.: The earth's ionosphere: plasma physics and electrodynamics,
Academic Press, Inc., San Diego, California, 1989.
Kelley, M. C., Starr, J. A., and Mozer, F. S.: Relationship between
magnetospheric electric fields and the motion of auroral forms,
J. Geophys. Res., 76, 5256–5277, 1971.
Kepko, L., Kivelson, M. G., McPherron, R. L., and Spence, H. E.: Relative
timing of substorm onset phenomena, J. Geophys. Res., 109, A04203,
https://doi.org/10.1029/2003JA010285, 2004.
Lighthill, M. J. and Whitham, G. B.: On kinematic waves. II. A theory of
traffic flow on long crowded roads, P. Roy. Soc. Lond. A Mat., 229, 317–345,
1955.
Liou, K., Newell, P. T., and Meng, C.-I.: Seasonal effects on auroral
particle acceleration and precipitation, J. Geophys. Res., 106, 5531–5542,
2001.
Liu, W. W., Liang, J., Donovan, E. F., and Spanswick, E.: If substorm onset
triggers tail reconnection, what triggers substorm onset, J. Geophys. Res.,
117, A11220, https://doi.org/10.1029/2012JA018161, 2012.
Machida, S., Miyashita, Y., Ieda, A., Nosé, M., Nagata, D., Liou, K., Obara, T., Nishida, A., Saito, Y., and Mukai, T.: Statistical visualization of the Earth's magnetotail based on Geotail data and the implied substorm model, Ann. Geophys., 27, 1035–1046, https://doi.org/10.5194/angeo-27-1035-2009, 2009.
Mozer, F. S., Carlson, C. W., Hudson, M. K., Torbert, R. B., Parady, B.,
Yatteau, J., and Kelley, M. C.: Observations of paired electrostatic shocks
in the polar magnetosphere, Phys. Rev. Lett., 38, 292–295, 1977.
Newell, P. T., Meng, C. I., and Lyons, K. M.: Suppression of discrete aurorae
by sunlight, Nature, 381, 766–767, 1996.
Nielsen, E. and Greenwald, R. A.: Variations in ionospheric currents and
electric fields in association with absorption spikes during substorm
expansion phase, J. Geophys. Res., 83, 5645–5654, 1978.
Nishimura, Y., Lyons, L. R., Zou, S., Xing, X., Angelopoulos, V., Mende, S. B., Bonnell, J. W., Larson, D., Auster, U., Hori, T., Nishitani, N., Hosokawa, K., Sofko, G., Nicolls, M., and Heinselman, C.: Preonset time sequence of auroral substorms:
Coordinated observations by all-sky imagers, satellites, and radars,
J. Geophys. Res., 115, A00108, https://doi.org/10.1029/2010JA015832, 2010.
Oguti, T.: Hydrogen emission and electron aurora at the onset of the auroral
breakup, J. Geophys. Res., 78, 7543–7547, 1973.
Oguti, T.: Introduction to auroral physics, Laboratory for
Solar-Terrestrial Environment, Nagoya University, 2010 (in Japanese).
Oguti, T., Kitamura, T., and Watanabe, T.: Global aurora dynamics campaign,
1985–1986, J. Geomagn. Geoelectr., 40, 485–504, 1988.
Prince, Jr., C. E. and Bostick Jr., F. X.: Ionospheric transmission of
transversely propagated plane waves at micropulsation frequencies and
theoretical power spectrums, J. Geophys. Res., 69, 3213–3234, 1964.
Radoski, H. R.: Highly asymmetric MHD resonances: The guided poloidal mode,
J. Geophys. Res., 72, 4026–4027, 1967.
Runov, A., Angelopoulos, V., Zhou, X.-Z., Zhang, X.-J., Li, S., Plaschke,
F., and Bonnell, J.: A THEMIS multicase study of dipolarization fronts in
the magnetotail plasma sheet, J. Geophys. Res., 116, A05216,
https://doi.org/10.1029/2010JA016316, 2011.
Saka, O., Hayashi, K., and Thomsen, M.: First 10 min intervals of Pi2 onset at
geosynchronous altitudes during the expansion of energetic ion regions in
the nighttime sector, J. Atmos. Sol.-Terr. Phy., 72, 1100–1109, 2010.
Saka, O., Hayashi, K., and Koga, D.: Periodic aurora surge propagating
eastward/westward at poleward boundary of aurora zone during the first 10
min intervals of Pi2 onset, J. Atmos. Sol.-Terr. Phy., 80, 285–295,
https://doi.org/10.1016/j.jastp.2012.02.010, 2012.
Saka, O., Hayashi, K., and Thomsen, M.: Pre-onset auroral signatures and subsequent development of substorm auroras: a development of ionospheric loop currents at the onset latitudes, Ann. Geophys., 32, 1011–1023, https://doi.org/10.5194/angeo-32-1011-2014, 2014.
Sato, N., Nagaoka, T., Hashimoto, K., and Saemundsson, T.: Conjugacy of
isolated auroral arcs and nonconjugate auroral breakups, J. Geophys. Res.,
103, 11641–11652, 1998.
Sato, T. and Okuda, H.: Ion-acoustic double layers, Phys. Rev. Lett., 44,
740–743, 1980.
Shiokawa, K., Baumjohann, W., and Haerendel, G.: Braking of high-speed flows
in the near-Earth tail, Geophys. Res. Lett., 24, 1179–1182, 1997.
Temerin, M., Cerny, K., Lotko, W., and Mozer, F. S.: Observations of double
layers and solitary waves in the auroral plasma, Phys. Rev. Lett., 48,
1176–1179, 1982.
Thomsen, M. F., Korth, H., and Elphic, R. C.: Upper cutoff energy of the
electron plasma sheet as a measure of magnetospheric convection strength,
J. Geophys. Res., 107, SMP 25-1–SMP 25-18, https://doi.org/10.1029/2001JA000148, 2002.
Tsyganenko, N. A.: A magnetospheric magnetic field model with a warped tail
current sheet, Planet. Space Sci., 37, 5–20, 1989.
Wahlund, J.-E., Opgenoorth, H. J., Haggstrom, I., Winser, K. J., and Jones,
G. O.: EISCAT observations of topside ionospheric outflows during auroral
activity: revisited, J. Geophys. Res., 97, 3019–3017, 1992.
Whitham, G. B.: Linear and nonlinear waves, A Wiley-Interscience Publication,
John Wiley & Sons, Inc., New York, 1999.
Short summary
Flow channel extending in north–south directions is produced in the initial pulse of Pi2 pulsations associated with the field line dipolarization. Drifts in the ionosphere of the order of kilometers per second accumulated plasmas at the low-latitude end of the flow channel. The plasma compression in the ionosphere produced field-aligned currents, parallel electric fields, and auroral expansion. We called the compressive ionosphere a "dynamic ionosphere".
Flow channel extending in north–south directions is produced in the initial pulse of Pi2...