ANGEOAnnales GeophysicaeANGEOAnn. Geophys.1432-0576Copernicus PublicationsGöttingen, Germany10.5194/angeo-34-1243-2016The story of plumes: the development of a new conceptual framework for
understanding magnetosphere and ionosphere couplingMoldwinMark B.mmoldwin@umich.eduhttps://orcid.org/0000-0003-0954-1770ZouShashaHeineTomhttps://orcid.org/0000-0003-1286-364XClimate and Space Sciences and Engineering, University of Michigan, Ann
Arbor, USAMark B. Moldwin (mmoldwin@umich.edu)21December201634121243125329August20169November201626November2016This work is licensed under a Creative Commons Attribution 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/This article is available from https://angeo.copernicus.org/articles/34/1243/2016/angeo-34-1243-2016.htmlThe full text article is available as a PDF file from https://angeo.copernicus.org/articles/34/1243/2016/angeo-34-1243-2016.pdf
The name “plume” has been given to a variety of plasma structures in the
Earth's magnetosphere and ionosphere. Some plumes (such as the plasmasphere
plume) represent elevated plasma density, while other plumes (such as the
equatorial F region plume) represent low-density regions. Despite these
differences these structures are either directly related or connected in the
causal chain of plasma redistribution throughout the system. This short
review defines how plumes appear in different measurements in different
regions and describes how plumes can be used to understand
magnetosphere–ionosphere coupling. The story of the plume family helps
describe the emerging conceptual framework of the flow of
high-density–low-latitude ionospheric plasma into the magnetosphere and
clearly shows that strong two-way coupling between ionospheric and
magnetospheric dynamics occurs not only in the high-latitude auroral zone and
polar cap but also through the plasmasphere. The paper briefly reviews,
highlights and synthesizes previous studies that have contributed to this new
understanding.
There are three main classes of plumes that are described in the literature:
plasmaspheric plumes observed in the inner magnetosphere, storm-enhanced
density (SED) plumes observed in the midlatitude ionosphere (primarily the
topside ionosphere) and equatorial plumes (also called bubbles, bite-outs or
depletions) observed in the F region equatorial ionosphere and associated
with spread F. Plasmaspheric and SED plumes are defined as high-density
regions, while equatorial plumes are low-density regions. Each of these
phenomena was discovered by multiple diagnostic techniques independently.
However, over the last 15 or so years they have been connected to each other
by using multi-instrument studies (primarily the NASA
IMAGE EUV (Inner Magnetopause to Aurora Global Experiment Extreme Ultraviolet Imager) instrument, global arrays
of Global Positioning System (GPS) dual-frequency receivers, incoherent
scatter radars and a suite of satellites able to measure the low-energy
plasma in the inner magnetosphere) and the first two-way coupled
magnetosphere–ionosphere global models. This paper will first briefly
describe each of the different plumes independently (starting from the
largest scale and moving to smallest scale and from the magnetosphere to the
ionosphere) and then will synthesize the literature that has led to a new
understanding of magnetosphere–ionosphere (MI) coupling. What is now clear
is that plumes connect the equatorial F region ionosphere to the dayside
magnetopause and the nightside magnetotail plasma sheet (e.g., Su et al.,
2001a, b; Horvath and Lovell, 2011; Walsh et al., 2014a, b; Foster et al.,
2014). Through the formation and evolution of the different plumes, they
impact wave generation and wave–particle interactions (e.g., Summers et al.,
2008; Chen et al., 2012; Halford et al., 2015), particle precipitation
(Spasojević and Fuselier, 2009; Yuan et al., 2011, 2013), ion outflow
(e.g., Zeng and Horowitz, 2008; Tu et al., 2007), local-time asymmetries in
ULF wave field-line resonance (FLR) signatures (e.g., Archer et al., 2015;
Ellington et al., 2016), satellite communication and navigation systems
(Ledvina et al., 2004; Basu et al., 2005; Datta-Barua et al., 2014), and even
the coupling efficiency of the solar wind to the magnetosphere (Borovsky and
Denton, 2006; Borovsky et al., 2013; Ouellette et al., 2016; Fuselier et al.,
2016). Though we now have a new appreciation and understanding of plumes,
there are still many unanswered questions on their formation (e.g., Kelley et
al., 2004; Horvath and Lovell, 2011; Zou et al., 2013, 2014; Borovsky et al.,
2014) and impact on global magnetospheric dynamics (Borovsky et al., 1997;
McFadden et al. 2008; Walsh et al., 2014, 2015). We propose that the shift in
our conceptual understanding of the plasmasphere (Carpenter and Lemaire,
2004) now needs to extend down to the ionosphere and include a framework that
connects the three-dimensional plasmasphere–ionosphere–magnetosphere
system. This short review highlights and synthesizes work performed since the
launch of the IMAGE spacecraft in 2000 that has enabled the development of
the validation of our understanding of the flow of dense plasma from the
equatorial ionosphere into the Earth's plasma sheet.
Plasmaspheric plume
A dawn–dusk asymmetry in the shape of the plasmapause was observed in the
earliest investigations of the plasmasphere (e.g., Carpenter, 1966) and was
referred to as the duskside bulge (e.g., Chappell, 1974). Regions of
high-density plasma were also observed beyond the plasmapause in the earliest
high-inclination low-Earth orbit (e.g., Taylor et al., 1970, 1971) and
equatorial elliptical and geosynchronous orbit satellite missions (e.g.,
Chappell, 1974; Higel and Lei, 1984; McComas et al., 1993). These were called
plasmaspheric “tails” (Chappell, 1975; Maynard and Chen, 1975) or detached
plasma or blobs (e.g., Chappell et al., 1970). Ober et al. (1997) were the
first to call these features plumes in a paper's title. Soon after their
observation, there were a number of modeling studies that suggested they were
formed by dynamic sunward convection electric fields peeling away the outer
layers of the plasmasphere forming the bulge and long tails towards the
dayside magnetosphere (e.g., Chen and Wolf, 1972; Chen and Grewbowsky, 1978;
Lemaire, 2000; Nishida, 1966).
Figure 1 shows an observation of three successive orbits of the Combined Release and Radiation Effects
Satellite (CRRES) in the same
local-time sector, showing the appearance of density structure beyond the
main plasmapause (Moldwin et al., 2004). CRRES had a 10 h orbit, so
significant differences in the high-density distribution are observed from
one orbit to the next as well as significant outward radial motion of the
innermost plasmapause location. The launch of the IMAGE EUV instrument
enabled for the first time global observations of the plasmasphere and the
dynamic formation and evolution of plasmaspheric plumes (e.g., Sandel et al.,
2003; Goldstein, 2004; Goldstein, 2006). Figure 2 shows a sequence of IMAGE
EUV-inferred plasmapause and plume locations as a function of time
(Spasojević et al., 2003). The images are approximately an hour apart and
show the westward edge of the bulge co-rotate towards the dusk sector, while
the eastward edge of the plume stays nearly fixed in the dusk sector,
resulting in a narrowing and elongation into a tail-like feature reminiscent
of the initial magnetohydrodynamic (MHD) modeling done in
the 1970s.
CRRES plasma-wave-inferred plasma density profiles of three
successive orbit legs passing through the same local-time sector. Note the
innermost plasmapause moves from L of 3 to 3.4 to 4 and that dense plasma
structure appears over the 30 h of the three orbits (from Moldwin et al.,
2004).
Plasmapause locations inferred from IMAGE EUV observations from
26–27 June 2001, showing the formation of a plasmaspheric plume and a
morningside shoulder (from Spasojević et al., 2003).
Over the years, using a wide variety of measurement techniques, the general
properties and characteristics of plumes have been determined. They are often
long-lived, being observed for days at geosynchronous orbit (e.g., Borovsky et
al., 2014), are usually narrow in longitude and appear at all longitudes/MLT
(e.g., Moldwin et al., 1994), can have significant structure (e.g., Moldwin
et al., 1994, 1995; Darrouzet, et al., 2008; Sibanda et al., 2012), and can
exist at any level of geomagnetic activity – though they are primarily
associated with enhancements in activity (though not necessarily storms)
(Moldwin et al., 2004). Figure 3 shows the occurrence of plumes observed by
CRRES as a function of the Kp index compared to the distribution of Kp
observed during the CRRES mission lifetime. The figure shows that plumes primarily
occur for enhanced levels of Kp (> 3) but can be observed at all
levels of activity.
The distribution of Kp during the entire CRRES mission (blue bars)
and for intervals when CRRES observed plasmaspheric plumes beyond the
innermost plasmapause (from Moldwin et al., 2004).
An IMAGE EUV plasmasphere image and the coincident GPS TEC map over
North America showing that the boundary of the SED plume (red lines) matches
the boundary of the location of the plasmaspheric plume (from Foster et al.,
2002).
Many recent simple and sophisticated models of the inner-magnetosphere plasma
distribution have had success in explaining the formation, dynamics and
complex structure of plasmasphere plumes (e.g., Goldstein et al., 2005b,
2014; He et al., 2013; Ridley et al., 2014; Nakano et al., 2014). These
models all show plume formation though they take a variety of approaches by
either modeling the ionosphere–plasmasphere system or the inner
magnetosphere. One example of the outcome of the modeling studies is the
demonstration of the clear role of MI coupling has on the formation and
evolution of plumes. Goldstein et al. (2003, 2005b) examined the role that
sub-auroral polarization streams (SAPS) have on plume formation and
structure. SAPS are regions in which large ionospheric electric fields are
observed and are due to region 2 field-aligned current (FAC) through the
low-conductivity midlatitude trough region (e.g., Foster and Vo, 2002).
Inclusion of a dusk-side SAPS feature in their model, clearly helped
reproduce the observed plume structure better than the inclusion of only
simple global convection electric fields.
SED plume
An increase in ionospheric density in the aftermath of geomagnetic
disturbances at midlatitudes has been long observed (see review by Mendillo,
2007). The earliest studies identified the recurrent feature of a “positive
phase” (density enhancement) routinely in the dusk sector (and hence often
called the positive-phase dusk effect and more recently storm-enhanced
density (SED)). This was initially observed in single-station ionosondes,
then radio beacons, then ISR (e.g., Foster, 1993), then GPS networks (e.g.,
Coster and Skone, 2009) and then sophisticated data assimilation models
combining many different datasets (e.g., Garner et al., 2005). As multipoint
measurements became more common (e.g., Su et al., 2001b), the name plumes
began to appear, and with the seminal work of Foster et al. (2002) connecting
the ionospheric SED signature with the plasmaspheric plume feature, the term
SED plume began to appear regularly (e.g., Yizengaw et al., 2006; Foster,
2008). These SED plumes are observed in all MLT sectors but are
preferentially observed in the American sector due to the tilt of the dipole
geomagnetic field (e.g., Foster et al., 2008; Yizengaw et al., 2006; Coster
et al., 2007; Thomas et al., 2016). The largest values of TEC are also
observed in the American sector (Coster et al., 2007). Like plasmaspheric
plumes, SED ionospheric plumes are associated with geomagnetic storms and
enhanced geomagnetic activity.
Figure 4 shows the observational evidence showing that plasmaspheric plumes
and SED plumes are the ionospheric and magnetospheric manifestations of the
flow of low-L/low-latitude high-density plasma to higher-L/latitudes and was
obtained by combining IMAGE EUV observations of the plasmaspheric plume with
TEC observations of the ionospheric SED plume (Foster et al., 2002). This
paper unambiguously connected SED ionospheric plumes with plasmaspheric
plumes and showed that a new three-dimensional topside
ionosphere–plasmasphere–magnetosphere flux tube conceptual framework is
needed to understand plasma redistribution within the MI system.
A schematic of the flux tube mapping of the IMAGE EUV plasmasphere
(a) and the plasmaspheric plume (b) overlaid on the IMAGE
EUV image projected onto the equatorial plane. After the image was taken, the
IMAGE RPI instrument sampled this region during its inbound orbit pass and
observed the density structure shown in the inset. Note that there is a clear
plume (b) at higher L than the main plasmasphere (a)
(from Garcia et al., 2003).
The GPS TEC tomographic reconstruction of a meridional cross section
of the midlatitude to polar cap ionosphere showing the main F region
ionosphere, midlatitude trough region and auroral precipitation-enhanced
densities. The dotted line labeled plasmapause was extracted from the
concurrent plasmapause location from IMAGE EUV. The top panel shows the
topside ionosphere–plasmasphere transition height (with different color bar)
(from Yizengaw and Moldwin, 2005).
Further evidence connecting the two features was also presented by combining
the IMAGE EUV observation of the plume with the in situ density observation
taken during the subsequent fly-through of the plume at a lower altitude (e.g.,
Garcia et al., 2003). Figure 5 shows a schematic of the field-aligned flux
tube high-density regions mapping to the equatorial plane picture of the
plasmaspheric plume taken by IMAGE EUV. The high-density regions labeled A
and B are also indicated in the Radio Plasma Imager (RPI) plasma wave
spectrogram inset. In addition, Yizengaw and Moldwin (2005) combined
tomographic reconstructions of ionospheric density profiles with the mapped
location of the plasmapause as determined by IMAGE EUV and showed that the
ionospheric midlatitude trough at F region and topside ionosphere altitudes
is collocated with the plasmapause (Fig. 6). Numerous subsequent observations
of in situ plasmaspheric plume density associated with ionospheric SED plume
enhancements have been made by satellites in low-Earth orbit (e.g., Lin et
al., 2007) and the Van Allen probes (e.g., Foster et al., 2014). These
studies found that the ionospheric and plasmaspheric plumes have similar
behavior in their density variability and location of the steep density
gradients indicating that the SED ionospheric plumes maps into the
ionosphere. Coster et al. (2003) and Yuan et al. (2009) determined the
vertical altitude density profile within a SED plume and found that about
half of the total TEC is above 800 km (Fig. 7), showing that SED plumes
contain redistributed plasma (not just enhanced F region peak densities) and
are clearly connected to the dense plasmaspheric plasma in the magnetosphere.
The topside “heavy” distribution of the SED plume shows that the plasma is
due to the redistribution of uplifted F region plasma and also downflowing
plasmaspheric plasma (e.g., Bailey and Sellek, 1992). A modeling study showed
the complex interplay of plasma flows in the generation of super-fountain
effect equatorial dynamics (Lu et al., 2013) that can create enhanced and
higher-latitude equatorial anomaly features that can connect to SED features. Recent studies by Zou et al. (2013, 2014) using multiple
instruments, in particular the Poker Flat incoherent scatter radar (PFISR),
as well as Zou and Ridley (2016), using the Global Ionosphere–Thermosphere
Model (GITM), highlighted the importance of the interplay among the
convection flows, thermospheric winds and ambipolar diffusion within the SED
plume in determining the density structures within the plume and the fate of
the plume. Downward plasma flows within the plumes were reported on the
dayside ionosphere due to a combination of enhanced poleward thermospheric
winds and enhanced ambipolar diffusion (Zou et al., 2014, 2016).
A vertical density profile in a SED plume at 17:45 UT (solid line)
observed with the Millstone Hill incoherent scatter radar on 20 November 2003
compared with a quiet-time reference profile taken on 19 November 2003
(dashed line). Note that the topside ionosphere is greatly enhanced (from
Yuan et al., 2009).
The storm time (top) plasmasphere showing color contours of density
and black line contours of electric potential. The red triangles show where
the TEC = 50 TECU maps to the equatorial plane. The (bottom panel)
ionosphere shows color contours of the TEC, and the black contour line is
where TEC = 50 TECU (from Huba and Sazykin, 2014).
The equatorial ionosphere showing the flow pattern associated with
the fountain effect of moving low-altitude equatorial plasma to a higher
altitude (from Blitza, 2016).
As the SED density convects poleward towards the cusp (in the ionosphere) and
sunward towards the dayside magnetopause (in the magnetosphere), a plume of
high density is observed in the polar cap ionosphere (e.g., Steele and
Cogger, 1996; Foster et al., 2005) and at high altitudes on open field lines
over the polar cap (e.g., Tu et al., 2007). This so-called
tongue of ionization (TOI) connects the plume with cusp ion outflow (e.g.,
Zeng and Horowitz, 2008; Walsh et al., 2014b) and dense ionospheric density
contributions to the plasma sheet (e.g., Elphic et al., 1997; Borovsky et
al., 1997).
There has been considerable modeling of the ionospheric SED plume (e.g., Lin
et al., 2005) and of the plasmaspheric plume (e.g., Huba and Krall, 2013),
but recently the first self-consistent model of the ionosphere and
magnetosphere electric field drivers has been done with the SAMI3-RCM
simulation of the 31 March 2001 geomagnetic storm (Huba and Sazykin, 2014).
Figure 8 shows the projection of electron density in the equatorial plane and
a synthetic global TEC map showing how the plasmaspheric plume maps to the
ionospheric SED plume. The model used inner-magnetospheric electric fields
from the Rice Convection Model (RCM) to drive the
SAMI3 (another model of the ionosphere) ionosphere–plasmasphere
system self-consistently and found that the penetration electric fields
created the SED at low and midlatitudes and this ionospheric structure mapped
to the plasmaspheric plume in the equatorial magnetosphere.
Equatorial plasma plumes
The equatorial ionosphere is often considered disconnected from the rest of
the magnetosphere since the geomagnetic field threads the ionosphere
horizontally. However, it has been well known that storm time electric fields
can penetrate to the equatorial region, enhancing the equatorial electrojet
driving a vertical uplift of the plasma and through the fountain effect
creating the equatorial anomalies (e.g., Abdu, 1997; Tsurutani et al., 2004)
(Fig. 9). The term anomaly was given to these regions as it was originally
expected that the peak ionospheric density should be at the subsolar point,
but instead it was observed that there was a minima at the equator and two
peaks of enhanced density at about ±15∘ off the geomagnetic
equator (Appleton, 1946). The equatorial anomalies are regions of enhanced
ionospheric density that are often observed in the dayside through the dusk
sector and are modulated by geomagnetic activity and neutral winds (e.g.,
Abdu et al., 1991). The anomalies arise due to an
E×B uplift of the F region plasma due to an
equatorial horizontal electric field. The lifted plasma then settles
gravitationally along the magnetic field at higher latitudes. In addition,
the uplift of the equatorial ionosphere due to enhanced E fields at
dusk often sets off plasma instabilities (e.g., Basu et al., 1980; Kelley et
al., 2011) that gives rise to low-density bubbles or plumes. Note that in
this context the terms bubble and plumes are used to describe low-density
regions and the plasma motion associated with these regions (e.g., Bernhardt,
2007; Krall et al., 2010). Some of the small-scale density structures have
been suggested to be convected to midlatitudes in the SED plumes, giving rise
to midlatitude irregularity as well (e.g., Horvath and Lovell, 2011).
During large storms, the F region ionosphere can be lifted to very high
altitudes, giving rise to the so-called super-fountain effect (e.g., Lu et al.,
2013) and extreme values of TEC at midlatitudes by moving the equatorial
anomaly further poleward (e.g., Mannucci et al., 2005). During superstorms,
this redistribution of dense equatorial plasma to midlatitudes (and from the
inner plasmasphere to the outer plasmasphere) enables this plasma to be
caught up in the sunward convection flow forming the midlatitude SED and
plasmaspheric plume. The common sunward convection trajectories of these two
dense plasma regions further demonstrate their connection (e.g., Foster et
al., 2007). The mapping of ionospheric SAPS electric fields to the outer edge of the plasmaspheric plume also
demonstrate the connection (e.g., Foster et al., 2007; Goldstein et al.,
2005b; Lin et al., 2007). Since the equatorial dense plasma reaches the
midlatitudes through the fountain effect, it is distributed along the flux
tube at a higher altitude than the “normal” F region peak, giving rise to the
heavy topside density distribution. The enhanced density in the
plasmaspheric plumes and SEDs continue to
E×B drift sunward impacting the dayside
magnetopause (e.g., Walsh et al., 2014) and forming the so-called TOI over the polar cap (e.g., Thomas et al., 2013).
Conclusions
The story of the plume family developed over the last 15 years or so is the
story of more fully understanding magnetosphere–ionosphere coupling. We now
have evidence (both observational and modeling) to show that there is a
redistribution of plasma from the equatorial ionosphere into the outer
plasmasphere that participates in inner-magnetospheric convection to the
dayside magnetopause and cusp region. This cold, dense plasma modulates
dayside reconnection, plasma and ULF wave generation and propagation, and
truly connects the topside ionosphere and magnetosphere through ion outflow, contributing to the mass density of the magnetotail plasma sheet. As reviewed
above, a significant number of studies published over the last 15 years
demonstrate that plumes tell us that there is strong two-way coupling between
the magnetosphere and ionosphere during geomagnetic activity – not only does
the ionosphere respond to magnetospheric forcing during storms, but through
its impact on wave generation, wave–particle interactions, ion outflow and
mass loading at the dayside magnetopause and in the magnetotail, dense
plasma plumes modulate the subsequent magnetospheric dynamics.
Data availability
No original data are described in this review paper. All data presented have been
published previously.
Acknowledgements
This work was partially support by NSF AGS 1450512. Shasha Zou would like to
acknowledge NSF AGS1342968 and NASA NNX14AF31G. The lead author thanks the
organizing committee of the International Symposium of Equatorial Aeronomy 14
Workshop held in Bahir Dar Ethiopia for the invitation to present a talk.
This paper is based on that presentation. The authors thank the editor and
the two referees for suggestions that significantly improved the
presentation. The topical editor,
P. J. Erickson, thanks J. Foster, D. Gallagher, and one anonymous referee for
help in evaluating this paper.
References
Abdu, M. A.: The Ninth International Symposium on Equatorial Aeronomy, Major
phenomena of the equatorial ionosphere-thermosphere system under disturbed
conditions, J. Atmos. Sol.-Terr. Phy., 59,
1505–1519, 1997.
Abdu, M. A., Sobral, J. H. A., de Paula, E. R., and Batista, I. S.: Magnetospheric
disturbance effects on the Equatorial Ionization Anomaly (EIA): an overview,
J. Atmos. Terr. Phys., 53,
757–771, 1991.Appleton, E. V.: Two Anomalies in the Ionosphere, Nature, 157,
691 pp., 10.1038/157691a0, 1964.
Archer, M. O., Hartinger, M. D., Walsh, B. M., Plaschke, F., and Angelopoulos,
V.: Frequency variability of standing Alfvén waves excited by fast
mode resonances in the outer magnetosphere, Geophys. Res. Lett., 42,
10150–10159, 2015.Bailey, G. J. and Sellek, R.: Field-aligned flows of H+ and He+ in the
mid-latitude topside ionosphere at solar maximum, Planet. Space
Sci., 40, 751–762, 1992.Basu, S., McClure, J., Basu, S., Hanson, W., and Aarons, J.: Coordinated study of equatorial scintillation and in situ and
radar observations of nighttime F region irregularities, J. Geophys.
Res., 85, 5119–5130, 1980.Basu, S., Makela, J. J., Sheehan, R. E., MacKenzie, E., Doherty, P., Wright,
J. W., Keskinen, M. J., Pallamraju, D., Paxton, L. J., and Berkey, F. T.: Two
components of ionospheric plasma structuring at midlatitudes observed during
the large magnetic storm of 30 October 2003, Geophys. Res. Lett., 32, L12S06,
10.1029/2004GL021669, 2005.Bernhardt, P. A.: Quasi-analytic models for density bubbles and
plasma clouds in the equatorial ionosphere: 2. A simple Lagrangian transport
model, J. Geophys. Res., 112, A11310, 10.1029/2007JA012287, 2007.Bilitza, D.: International Reference Ionosphere,
http://iri.gsfc.nasa.gov/, last access: 24 August 2016.Borovsky, J. E. and Denton, M. H.: Effect of plasmaspheric drainage plumes on
solar-wind/magnetosphere coupling, Geophys. Res. Lett., 33, L20101,
10.1029/2006GL026519, 2006.Borovsky, J. E., Thomsen, M. F., and McComas, D. J.: The
superdense plasma sheet: Plasmaspheric origin, solar wind origin, or
ionospheric origin?, J. Geophys. Res., 102,
22089–22097, 10.1029/96JA02469, 1997.Borovsky, J. E., Denton, M. H., Denton, R. E., Jordanova, V. K., and Krall,
J.: Estimating the effects of ionospheric plasma on solar wind/magnetosphere
coupling via mass loading of dayside reconnection: Ion-plasma-sheet oxygen,
plasmaspheric drainage plumes, and the plasma cloak, J. Geophys. Res. Space
Phys., 118, 5695–5719, 10.1002/jgra.50527, 2013.Borovsky, J. E., Welling, D. T., Thomsen, M. F., and Denton, M. H.:
Long-lived plasmaspheric drainage plumes: Where does the plasma come from?,
J. Geophys. Res. Space Phys., 119, 6496–6520, 10.1002/2014JA020228,
2014.Carpenter, D. L.: Whistler studies of the plasmapause in the
magnetosphere: 1. Temporal variations in the position of the knee and some
evidence on plasma motions near the knee, J. Geophys. Res., 71,
693–709, 10.1029/JZ071i003p00693, 1966.Carpenter, D. L. and Lemaire, J.: The Plasmasphere Boundary Layer, Ann.
Geophys., 22, 4291–4298, 10.5194/angeo-22-4291-2004, 2004.
Chappell, C. R.: Detached plasma regions in the magnetosphere, J. Geophys.
Res., 79, 1861–1870, 1974.Chappell, C. R.: Ionosphere-magnetosphere coupling: 1. Thermal plasma,
Rev. Geophys., 13, 872–873, 10.1029/RG013i003p00872, 1975.Chappell, C. R., Harris, K. K., and Sharp, G. W.: The
morphology of the bulge region of the plasmasphere, J. Geophys. Res., 75, 3848–3861, 10.1029/JA075i019p03848,
1970.
Chen, A. J. and Wolf, R. A.: Effects on the plasmasphere of a time-varying
convection electric field, Planet. Space Sci., 20, 483–509, 1972.
Chen, A. J. and Grebowsky, J. M.: Dynamical interpretation of observed
plasmasphere deformations, Planet. Space Sci., 26, 661–672, 1978.Chen, L., Thorne, R. M., Li, W., Bortnik, J., Turner, D., and Angelopoulos,
V.: Modulation of plasmaspheric hiss intensity by thermal plasma density
structure, Geophys. Res. Lett., 39, L14103, 10.1029/2012GL052308, 2012.Coster, A. and Skone, S.: Monitoring storm-enhanced density using IGS
reference station data, S. J. Geod., 83, 345–351,
10.1007/s00190-008-0272-3, 2009.
Coster, A. J., Foster, J. C., and Erickson, P. J.: Monitoring the Ionosphere with GPS,
GPS World, May, 42–49, 2003.Coster, A. J., Colerico, M. J., Foster, J. C., Rideout, W., and
Rich, F.: Longitude sector comparisons of storm enhanced density, Geophys. Res. Lett., 34, L18105, 10.1029/2007GL030682, 2007.Darrouzet, F., Gallagher, D. L., André, N., Carpenter, D. L., Dandouras,
I., Décréau, P. M. E., De Keyser, J., Denton, R. E., Foster, J. C.,
Goldstein, J., Moldwin, M. B., Reinisch, B. W., Sandel, B. R., and Tu, J.:
Plasmaspheric density structures and dynamics: Properties observed by the
CLUSTER and IMAGE missions, Space Sci. Rev., 145, 55–106,
10.1007/s11214-008-9438-9, 2008.Datta-Barua, S., Walter, T., Bust, G. S., and Wanner, W.: Effects of
solar cycle 24 activity on WAAS navigation, Space Weather, 12, 46–63,
10.1002/2013SW000982, 2014.Ellington, S. M., Moldwin, M. B., and Liemohn, M. W.: Local time
asymmetries and toroidal field line resonances: Global magnetospheric
modeling in SWMF, J. Geophys. Res. Space Phys., 121, 2033–2045,
10.1002/2015JA021920, 2016.Elphic, R. C., Thomsen, M. F., and Borovsky, J. E.: Fate of the Outer
Plasmasphere, Geophys. Res. Lett., 24, 365–368, 10.1029/97GL00141,
1997.Foster, J. C.: Storm time plasma transport at middle and high
latitudes, J. Geophys. Res., 98, 1675–1689,
10.1029/92JA02032, 1993.
Foster, J. C.: Ionospheric-magnetospheric-heliospheric coupling: Storm-time
thermal plasma redistribution, Midlatitude Ionospheric Dynamics and
Disturbances, edited by: Kintner Jr, P. M., Coster, A. J., Fuller-Rowell, T.,
Mannucci, A. J., Mendillo, M., and Heelis, R., AGU, Washington, DC,
Geophys. Monogr. Ser., 181, 121–134, 2008.Foster, J. C. and Vo, H. B.: Average characteristics and activity
dependence of the subauroral polarization stream, J. Geophys. Res., 107, 1475, 10.1029/2002JA009409,
2002.Foster, J. C., Erickson, P. J., Coster, A. J., Goldstein, J., and Rich, F.
J.: Ionospheric signatures of plasmaspheric tails, Geophys. Res. Lett.,
29, 1623, 10.1029/2002GL015067, 2002.Foster, J. C., Coster, A. J., Erickson, P. J., Holt, J. M., Lind, F. D.,
Rideout, W., McCready, M., van Eyken, A., Barnes, R. J., Greenwald, R. A.,
and Rich, F. J.: Multiradar observations of the polar tongue of ionization,
J. Geophys. Res., 110, A09S31, 10.1029/2004JA010928, 2005.
Foster, J. C., Rideout, W., Sandel, B., Forrester, W. T., and Rich, F. J.: On the
relationship of SAPS to storm-enhanced density, J. Atmos.
Sol.-Terr. Phy., 69, 303–313, 2007.Foster, J. C., Erickson, P. J., Coster, A. J., Thaller, S., Tao, J.,
Wygant, J. R., and Bonnell, J. W.: Storm time observations of plasmasphere
erosion flux in the magnetosphere and ionosphere, Geophys. Res. Lett., 41,
762–768, 10.1002/2013GL059124, 2014.Fuselier, S. A., Burch, J. L., Cassak, P. A., Goldstein, J., Gomez, R. G.,
Goodrich, K., Lewis, W. S., Malaspina, D., Mukherjee, J., Nakamura, R.,
Petrinec, S. M., Russell, C. T., Strangeway, R. J., Torbert, R. B., Trattner,
K. J., and Valek, P.: Magnetospheric ion influence on magnetic reconnection
at the duskside magnetopause, Geophys. Res. Lett., 43, 1435–1442,
10.1002/2015GL067358, 2016.Garcia, L. N., Fung, S. F., Green, J. L., Boardsen, S. A., Sandel, B. R., and
Reinisch, B. W.: Observations of the latitudinal structure of plasmaspheric
convection plumes by IMAGE-RPI and EUV, J. Geophys. Res., 108, 1321,
10.1029/2002JA009496, 2003.Garner, T. W., Bust, G. S., Gaussiran II, T. L., and Straus, P. R.:
Variations in the midlatitude and equatorial ionosphere during the October
2003 magnetic storm, Radio Sci., 41, RS6S08, 10.1029/2005RS003399,
2006.Goldstein, J.: Simultaneous remote sensing and in situ observations of
plasmaspheric drainage plumes, J. Geophys. Res., 109, A03202,
10.1029/2003JA010281, 2004.
Goldstein, J.: Plasmasphere Response: Tutorial and Review of Recent
Imaging Results, Space Sci. Rev., 124, 203–216, 2006.Goldstein, J., Sandel, B. R., Hairston, M. R., and Reiff, P. H.: Control of
plasmaspheric dynamics by both convection and sub-auroral polarization
stream, Geophys. Res. Lett., 30, 2243, 10.1029/2003GL018390, 2003.Goldstein, J., Burch, J. L., and Sandel, B. R.:
Magnetospheric model of subauroral polarization stream, J. Geophys. Res.,
110, A09222, 10.1029/2005JA011135, 2005a.Goldstein, J., Sandel, B. R., Forrester, W. T., Thomsen, M. F., and Hairston, M.
R.: Global plasmasphere evolution 22–23 April 2001, J.
Geophys. Res., 110, A12218, 10.1029/2005JA011282, 2005b.Goldstein, J., Thomsen, M. F., and DeJong, A.: In situ
signatures of residual plasmaspheric plumes: Observations and simulation,
J. Geophys. Res. Space Phys., 119, 4706–4722,
10.1002/2014JA019953, 2014.Halford, A. J., Fraser, B. J., and Morley, S. K.: EMIC waves and
plasmaspheric and plume density: CRRES results, J. Geophys. Res. Space Phys.,
120, 1974–1992, 10.1002/2014JA020338, 2015.He, F., Zhang, X.-X., Chen, B., Fok, M.-C., and Zou, Y.-L.: Moon-based EUV
imaging of the Earth's Plasmasphere: Model simulations, J. Geophys. Res.
Space Phys., 118, 7085–7103, 10.1002/2013JA018962, 2013.Higel, B. and Lei, W.: Electron density and plasmapause
characteristics at 6.6 RE: A statistical study of the GEOS 2 relaxation
sounder data, J. Geophys. Res., 89, 1583–1601,
10.1029/JA089iA03p01583, 1984.Horvath, I. and Lovell, B. C.: Storm-enhanced plasma density (SED)
features, auroral and polar plasma enhancements, and rising topside bubbles
of the 31 March 2001 superstorm, J. Geophys. Res., 116, A04307,
10.1029/2010JA015514, 2011Huba, J. and Krall, J.: Modeling the plasmasphere with
SAMI3, Geophys. Res. Lett., 40, 6–10, 10.1029/2012GL054300, 2013.Huba, J. D. and Sazykin, S.: Storm time ionosphere and plasmasphere
structuring: SAMI3-RCM simulation of the 31 March 2001 geomagnetic storm,
Geophys. Res. Lett., 41, 8208–8214, 10.1002/2014GL062110, 2014.Kelley, M. C., Vlasov, M. N., Foster, J. C., and Coster, A. J.: A quantitative explanation for the phenomenon known as
storm-enhanced density, Geophys. Res. Lett., 31, L19809,
10.1029/2004GL020875, 2004.Kelley, M. C., Makela, J. J., de La Beaujardière, O., and Retterer, J.:
Convective ionospheric storms: A review, Rev. Geophys., 49, RG2003,
10.1029/2010RG000340, 2011.Krall, J., Huba, J. D., Ossakow, S. L., and Joyce, G.: Equatorial spread F
fossil plumes, Ann. Geophys., 28, 2059–2069, 10.5194/angeo-28-2059-2010,
2010.Ledvina, B. M., Kintner, P. M., and Makela, J. J.: Temporal properties
of intense GPS L1 amplitude scintillations at midlatitudes, Radio Sci., 39,
RS1S18, 10.1029/2002RS002832, 2004.
Lemaire, J. F.: The formation plasmaspheric plumes, Phys. Chem. Earth, 25,
9–17, 2000.Lin, C. H., Richmond, A. D., Heelis, R. A., Bailey, G. J., Lu, G., Liu, J.
Y., Yeh, H. C., and Su, S.-Y.: Theoretical study of
the low- and midlatitude ionospheric electron density enhancement during the
October 2003 superstorm: Relative importance of the neutral wind and the
electric field, J. Geophys. Res., 110, A12312, 10.1029/2005JA011304, 2005.Lin, C. S., Yeh, H.-C., Sandel, B. R., Goldstein, J., Rich, F. J., Burke, W.
J., and Foster, J. C.: Magnetospheric Convection
near a Drainage Plume, J. Geophys. Res., 112, A05216,
10.1029/2006JA011819, 2007.Lu, G., Huba, J. D., and Valladares, C.: Modeling ionospheric super-fountain effect
based on the coupled TIMEGCM-SAMI3, J. Geophys. Res. Space Phys., 118, 2527–2535, 10.1002/jgra.50256, 2013.Mannucci, A. J., Tsurutani, B. T., Iijima, B., Komjathy, A., Wilson, B., Pi,
X., Sparks, L., Hajj, G., Mandrake, L., Gonzalez, W. D., Kozyra, J., Yumoto,
K., Swisdak, M., Huba, J. D., and Skoug, R.: Hemispheric Daytime Ionospheric
Response to Intense Solar Wind Forcing, in: Inner Magnetosphere Interactions:
New Perspectives from Imaging, edited by: Burch, J., Schulz, M., and Spence,
H., American Geophysical Union, Washington, DC, 10.1029/159GM20, 2005.Maynard, N. C. and Chen, A. J.: Isolated cold plasma regions: Observations
and their relation to possible production mechanisms, J. Geophys. Res., 80,
1009–1013, 10.1029/JA080i007p01009, 1975.McComas, D. J., Bame, S. J., Barraclough, B. L., Donart, J. R.,
Elphic, R. C., Gosling, J. T., Moldwin, M. B., Moore, K. R., and
Thomsen, M. F.: Magnetospheric plasma analyzer: Initial three-spacecraft
observations from geosynchronous orbit, J. Geophys. Res., 98, 13453–13465,
10.1029/93JA00726, 1993.McFadden, J. P., Carlson, C. W., Larson, D., Bonnell, J., Mozer, F. S., Angelopoulos, V., Glassmeier, K.-H., and Auster, U.: Structure of plasmaspheric plumes and their participation in magnetopause
reconnection: First results from THEMIS, Geophys. Res. Lett., 35,
L17S10, 10.1029/2008GL033677, 2008.Mendillo, M.: Storms in the ionosphere: Patterns and processes for
total electron content, Rev. Geophys., 44, RG4001,
10.1029/2005RG000193, 2006.
Moldwin, M. B., Thomsen, M. F., Bame, S. J., McComas, D. J., and Moore, K.
R.: An examination of the structure and dynamics of the outer plasmasphere
using multiple geosynchronous satellites, J. Geophys. Res., 99, 1475–11481,
1994.Moldwin, M. B., Thomsen, M. F., Bame, S. J., McComas, D., and Reeves, G. D.:
The fine-scale structure of the outer plasmasphere, J. Geophys. Res.,
100, 8021–8029, 10.1029/94JA03342, 1995.Moldwin, M. B., Howard, J., Sanny, J., Bocchicchio, J. D., Rassoul, H. K., and
Anderson, R. R.: Plasmaspheric plumes: CRRES observations of enhanced
density beyond the plasmapause, J. Geophys. Res., 109, A05202,
10.1029/2003JA010320, 2004.Nakano, S., Fok, M.-C., Brandt, P. C., and Higuchi, T.: Estimation of temporal evolution of the helium plasmasphere based on a
sequence of IMAGE/EUV images, J. Geophys. Res. Space Phys., 119, 3708–3723,
10.1002/2013JA019734, 2014.
Nishida, A.: Formation of plasmapause, or magnetospheric plasma knee, by the
combined action of magnetospheric convection and plasma escape from the tail,
J. Geophys. Res., 71, 5669–5679, 1966.Ober, D. M., Horwitz, J. L., Thomsen, M. F., Elphic, R. C., McComas, D. J.,
Belian, R. D., and Moldwin, M. B.: Premidnight plasmaspheric “plumes”, J.
Geophys. Res., 102, 11325–11334, 10.1029/97JA00562, 1997.Ouellette, J. E., Lyon, J. G., Brambles, O. J., Zhang, B., and Lotko, W.:
The effects of plasmaspheric plumes on dayside reconnection, J. Geophys. Res.
Space Phys., 121, 4111–4118, 10.1002/2016JA022597, 2016.Ridley, A. J., Dodger, A. M., and Liemohn, M. W.: Exploring the efficacy of different electric field models in driving a model
of the plasmasphere, J. Geophys. Res. Space Phys., 119, 4621–4638, 10.1002/2014JA019836, 2014.Sandel, B. R., Goldstein, J., Gallagher, D. L., and Spasojevic, M.:
Extreme Ultraviolet Imager observations of the structure and dynamics of the
plasmasphere, Space Sci. Rev., 109, 25–46, 10.1023/B:SPAC.0000007511.47727.5b, 2003.Sibanda, P., Moldwin, M. B., Galvan, D. A., Sandel, B. R., and Forrester, T.:
Quantifying the azimuthal plasmaspheric density structure and
dynamics inferred from IMAGE EUV, J. Geophys. Res., 117, A11204,
10.1029/2012JA017522, 2012.Spasojević, M., Goldstein, J., Carpenter, D. L., Inan, U. S., Sandel, B.
R., Moldwin, M. B., and Reinisch, B. W.: Global response of the plasmasphere
to a geomagnetic disturbance, J. Geophys. Res., 108, 1340,
10.1029/2003JA009987, A9, 2003.Spasojević, M. and Fuselier, S. A.: Temporal evolution of proton
precipitation associated with the plasmaspheric plume, J. Geophys. Res., 114,
A12201, 10.1029/2009JA014530, 2009.Steele, D. P. and Cogger, L. L.: Polar patches and the
“tongue of ionization”, Radio Sci., 31, 667–677, 10.1029/96RS00369, 1996.Su, Y.-J., Borovsky, J. E., Thomsen, M. F., Dubouloz, N.,
Chandler, M. O., Moore, T. E., and Bouhram, M.: Plasmaspheric
material on high-latitude open field lines, J. Geophys. Res., 106, 6085–6095, 10.1029/2000JA003008, 2001a.
Su, Y.-J., Thomsen, M. F., Borovsky, J. E., and Foster, J. C.: A linkage
between polar patches and plasmaspheric drainage plumes, Geophys. Res. Lett.,
28, 111–113, 2001b.Summers, D., Ni, B., Meredith, N. P., Horne, R. B., Thorne, R. M., Moldwin, M. B.,
and Anderson, R. R.: Electron scattering by whistler-mode ELF hiss in
plasmaspheric plumes, J. Geophys. Res., 113, A04219, 10.1029/2007JA012678, 2008.
Taylor, H. A., Brinton, H. C., and Deshmukh, A. R.: Observations of irregular
structure in thermal ion distributions in the duskside magnetosphere, J.
Geophys. Res., 75, 2481–2489, 1970.Taylor Jr., H. A., Grebowsky, J. M., and Walsh, W. J.: Structured variations of the
plasmapause: Evidence of a corotating plasma tail, J. Geophys. Res., 76, 6806–6814, 10.1029/JA076i028p06806, 1971.Thomas, E. G., Baker, J. B. H., Ruohoniemi, J. M., Coster, A. J., and Zhang, S.-R.: The geomagnetic storm time response of GPS total
electron content in the North American sector, J. Geophys. Res. Space
Phys., 121, 1744–1759, 10.1002/2015JA022182, 2016.Tsurutani, B., Mannucci, A.; Iijima, B., Abdu, M. A., Sobral, J. H. A.,
Gonzalez, W., Guarnieri, F., Tsuda, T., Saito, A., Yumoto, K., Fejer, B.,
Fullerrowell, T. J., Kozyra, J., Foster, J. C., Coster, A., and Vasyliunas,
V. M.: Global dayside ionospheric uplift and enhancement associated with
interplanetary electric fields, J. Geophys. Res., 109, A08302,
10.1029/2003JA010342, 2014.Tu, J.-N., Dhar, M., Song, P., Reinisch, B. W., Green, J. L.,
Benson, R. F., and Coster, A. J.: Extreme polar cap density
enhancements along magnetic field lines during an intense geomagnetic storm, J. Geophys. Res., 112, A05201, 10.1029/2006JA012034, 2007.
Walsh, B. M., Phan, T. D., Sibeck, D. G., and Souza, V. M.: The
plasmaspheric plume and magnetopause reconnection, Geophys. Res. Lett., 41,
223–228, 10.1002/2013GL058802, 2014a.Walsh, B. M., Foster, J. C., Erickson, P. J., and Sibeck, D. G.:
Simultaneous Ground and Space-Based Observations of the Plasmaspheric Plume
and Magnetospheric Reconnection, Science, 343/6175, 1122–1125, 10.1126/science.1247212, 2014b.Walsh, B. M., Thomas, E. G., Hwang, K.-J., Baker, J. B. H., Ruohoniemi, J. M.,
and Bonnell, J. W.: Dense plasma and Kelvin-Helmholtz waves at Earth's
dayside magnetopause, J. Geophys. Res. Space Phys., 120, 5560–5573,
10.1002/2015JA021014, 2015.Yizengaw, E. and Moldwin, M. B.: The altitude extension of the
mid-latitude trough and its correlation with plasmapause position, Geophys.
Res. Lett., 32, L09105, 10.1029/2005GL022854, 2005.Yizengaw, E., Moldwin, M. B., and Galvan, D. A.: Ionospheric signatures of a
plasmaspheric plume over Europe, Geophys. Res. Lett., 33, L17103, 10.1029/2006GL026597, 2006.Yuan, Z., Zhao, L., Xiong, Y., Deng, X., and Wang, J.: Energetic particle
precipitation and the influence on the sub-ionosphere in the SED plume during
a super geomagnetic storm, J. Geophys. Res., 116, A09317, 10.1029/2011JA016821, 2011.Yuan, Z., Li, M., Xiong, Y., Li, H., Zhou, M., Wang, D., Huang, S., Deng, X., and
Wang, J.: Simultaneous observations of precipitating radiation belt
electrons and ring current ions associated with the plasmaspheric plume, J.
Geophys. Res. Space Phys., 118, 4391–4399, 10.1002/jgra.50432, 2013.Yuan, Z.-G., Deng, X.-H., Zhang, S.-R., Wan, W.-X., and
Reinisch, B. W.: F region behavior in the SED plume during a geomagnetic
superstorm: A case study, J. Geophys. Res., 114, A08303,
10.1029/2008JA013841, 2009.Zeng, W. and Horwitz, J. L.: Storm enhanced densities
(SED) as possible sources for Cleft Ion Fountain dayside ionospheric
outflows, Geophys. Res. Lett., 35, L04103, 10.1029/2007GL032511, 2008.Zou, S. and Ridley, A. J.: Modeling of the Evolution of Storm-Enhanced
Density Plume during the 24 to 25 October 2011 Geomagnetic Storm, in:
Magnetosphere-Ionosphere Coupling in the Solar System, edited by: Chappell, C. R., Schunk, R.
W., Banks, P. M., Burch, J. L., and Thorne, R. M., John Wiley & Sons,
Inc., Hoboken, NJ, USA, 10.1002/9781119066880.ch16, 2016.Zou, S., Ridley, A. J., Moldwin, M. B., Nicolls, M. J., Coster, A. J., Thomas, E. G., and Ruohoniemi, J. M.: Multi-instrument
observations of SED during 24–25 October 2011 storm: Implications for SED
formation processes, J. Geophys. Res. Space Phys., 118, 7798–7809, 10.1002/2013JA018860, 2013.Zou, S., Moldwin, M. B., Ridley, A. J., Nicolls, M. J., Coster, A. J., Thomas, E.
G., and Ruohoniemi, J. M.: On the generation/decay of
the storm-enhanced density (SED) plumes: role of the convection flow and
field-aligned ion flow, J. Geophys. Res., 119, 543–8559, 10.1002/2014JA020408, 2014.