The 12th International Conference on Substorms
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Editorial Board (June 2016)
Editor-in-Chief
Yasuo Ogawa, Tokyo Institute of Technology, Japan

Vice Editors-in-Chief
Masato Furuya, Hokkaido University, Japan
Solid Earth Science

Nozomu Nishitani, Nagoya University, Japan
Space Science

Editors
Yosuke Aoki
Nanan Balan
Stephen Bannister
Shanaka de Silva
Koji Fukuma
Lin-Ni Hau
Hauke Hussmann
Attila Komjathy

Alexey Kuvshinov
Takuto Maeda
Koji Matsumoto
Mitsuhiro Nakagawa
Junichi Nakajima
Yasuhiro Nariyuki
Azusa Nishizawa
Keiji Ohtsuki

Taku Ozawa
Takeshi Sakanoi
Martha K. Savage
Benoit Taisne
Hiroshi Takenaka
Hiroaki Toh
Yih-Min Wu
Akimasa Yoshikawa

Hiroo Kanamori
Jun'ichiro Kawaguchi
Takafumi Matsui
Hitoshi Mizutani

Toshitaka Tsuda
Zhongliang Wu
Kiyoshi Yomogida

Advisory Board
Benjamin Fong Chao
Bernard Chouet
Yoshimori Honkura
Toshihiko Iyemori

Journal Scope
Earth, Planets and Space (EPS) is the official journal of the Society of Geomagnetism and Earth, Planetary
and Space Sciences, The Seismological Society of Japan, The Volcanological Society of Japan, The
Geodetic Society of Japan, and The Japanese Society for Planetary Sciences.
EPS is a peer-reviewed, open-access journal published under SpringerOpen. It is an international journal
covering scientific articles in the entire field of earth and planetary sciences, particularly geomagnetism,aeronomy, space science, seismology, volcanology, geodesy, and planetary science. EPS also welcomesarticles in new and interdisciplinary subjects, and technical reports on instrumentation and software.
The journal was launched in 1998 and has since published over 2700 articles. All of them are available forfree on SpringerLink:
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Submit your next research article to Earth, Planets and Space via:
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Yours sincerely,
Prof. Yasuo Ogawa
Editor-in-Chief, Earth, Planets and Space
editor-in-chief@earth-planets-space.org

Earth, Planets and Space
Shiokawa et al. Earth, Planets and Space (2016) 68:87
DOI 10.1186/s40623-016-0471-8

Open Access

PREFACESpecial issue “The 12th International
Conference on Substorms”
Kazuo Shiokawa1*, Mei‑Ching Fok2 and Masaki Fujimoto3
et al. 2015; Connors et al. 2015; Tanaka et al. 2015), andground magnetometer chains (Connors et al. 2016). In
addition, a review paper by Akasofu (2015) based on his
presentation at ICS-12 was published in Progress in Earthand Planetary Science. These papers provide a comprehensive overview of recent progress in research related to
substorms from solar wind to the ionosphere. We hopethat these publications provide resources for the understanding of the various physical processes that occur inthe magnetosphere and ionosphere during substorms.

The 12th International Conference on Substorms (ICS12) was held at the Ise-Shima Royal Hotel in Shima,
Japan, on November 10–14, 2014. There were 125 attendees including 68 from foreign countries. The ICS has
been held every 2 years since 1992 to discuss substorms,
which are fundamental global-scale disturbances in the
Earth’s magnetosphere. The year 2014 marked the 50th
anniversary of the first publication about substorms(Akasofu 1964). The conference included three tutorial
lecturers (Profs. S.-I. Akasofu, V. Angelopoulous, and D.
Baker), as well as many international scientists, to discuss
substorm processes in the tail, their interactions with theinner magnetosphere and the ionosphere, substorm currents and their dynamics and energetics, the role of MagnetoHydroDynamics (MHD) and kinetic instabilities,
storm–substorm relationships, ULF/ELF/VLF waves,and non-Earth substorm-like features. Prof. Akasofu also
gave an evening talk about the history of auroral research
since the nineteenth century with photographs thatinspired and intrigued the young scientists and students
in attendance.
This special issue presents 16 papers from the ICS-12
presentations. The topics and related papers are: controlof magnetospheric conditions by solar wind parameters(Kubyshkina et al. 2015; Sergeev et al. 2015; Troshichev
and Sormakov 2015), modeling of reconnection andinstabilities in the tail (Birn et al. 2015; Pritchett 2015;
Uchino and Machida 2015), relationships between relativistic electrons and pulsations in the inner magnetosphere (Antonova and Stepanova 2015; Hajra et al. 2015;
Teramoto et al. 2016), the effects of substorms on ionospheric irregularities and currents (Berngardt et al. 2015;
Cherniak and Zakharenkova 2015; Connors and Rostoker2015), auroral disturbances during substorms (Antonova

Authors’ contributions
All authors of this article served as the guest editors for this special issue. KS
prepared this preface with the agreement of the other authors. All authors
read and approved the final manuscript.
Author details
1
Institute for Space‑Earth Environmental Research, Nagoya University, Nagoya,Japan. 2 Goddard Space Flight Center, National Aeronautics and Space Admin‑
istration, Washington, DC, USA. 3 Institute of Space and Astronautical Science,
Japan Aerospace Exploration Agency, Sagamihara, Japan.
Acknowledgements
We thank the members of the science organizing committee for ICS 12,
the conference participants, and especially the authors of the papers in thisspecial issue. We are grateful to the referees who served to evaluate the con‑tributions and gave helpful comments and suggestions. We also express our
sincere appreciation and deep sorrow for the demise of late Olaf Amm, who
was initially a guest editor for this special issue, and made various helpful com‑ments and suggestions as a member of the science organizing committee,
but who passed away on December 16, 2014, 1 month after ICS‑12.
Competing interests
The authors declare that they have no competing interests.
Received: 12 May 2016 Accepted: 12 May 2016

References
Akasofu S‑I (1964) The development of the auroral substorm. Planet Space Sci
12:273–282. doi:10.1016/0032‑0633(64)90151‑5
Akasofu S‑I (2015) Auroral substorms as an electrical discharge phenomenon.
Progress Earth Planet Sci 2:20. doi:10.1186/s40645‑015‑0050‑9*Correspondence: shiokawa@nagoya‑u.jp
1
Institute for Space‑Earth Environmental Research, Nagoya University,
Nagoya, Japan
Full list of author information is available at the end of the article© 2016 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium,provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

1

The 12th International Conference on Substorms
Shiokawa et al. Earth, Planets and Space (2016) 68:87

Page 2 of 2

Kubyshkina M, Tsyganenko N, Semenov V, Kubyshkina D, Partamies N,
Gordeev E (2015) Further evidence for the role of magnetotail current
shape in substorm initiation. Earth Planets Space 67:139. doi:10.1186/
s40623‑015‑0304‑1
Pritchett PL (2015) Reconnection flow jets in 3D as a source of struc‑tured dipolarization fronts. Earth Planets Space 67:103. doi:10.1186/
s40623‑015‑0264‑5
Sergeev VA, Dmitrieva NP, Stepanov NA, Sormakov DA, Angelopoulos V, RunovAV (2015) On the plasma sheet dependence on solar wind and sub‑storms and its role in magnetosphere‑ionosphere coupling. Earth Planets
Space 67:133. doi:10.1186/s40623‑015‑0296‑x
Tanaka Y, Ogawa Y, Kadokura A, Partamies N, Whiter D, Enell CF, Brändström U,
Sergienko T, Gustavsson B, Kozlovsky A, Miyaoka H, Yoshikawa A (2015)
Eastward‑expanding auroral surges observed in the post‑midnight
sector during a multiple‑onset substorm. Earth Planets Space 67:182.
doi:10.1186/s40623‑015‑0350‑8
Teramoto M, Nishitani N, Nishimura Y, Nagatsuma T (2016) Latitudinal depend‑ence on the frequency of Pi2 pulsations near the plasmapause using
THEMIS satellites and Asian‑Oceanian SuperDARN radars. Earth Planets
Space 68:22. doi:10.1186/s40623‑016‑0397‑1
Troshichev OA, Sormakov DA (2015) PC index as a proxy of the solar windenergy that entered into the magnetosphere: 2. Relation to the interplan‑etary electric field EKL before substorm onset. Earth Planets Space 67:170.
doi:10.1186/s40623‑015‑0338‑4
Uchino H, Machida S (2015) Full‑particle simulations of instabilities in a thincurrent sheet of the magnetospheric system prior to substorm onset.
Earth Planets Space 67:165. doi:10.1186/s40623‑015‑0335‑7

Antonova EE, Stepanova MV (2015) The problem of the acceleration of elec‑
trons of the outer radiation belt and magnetospheric substorms. Earth
Planets Space 67:148. doi:10.1186/s40623‑015‑0319‑7
Antonova EE, Vorobjev VG, Kirpichev IP, Yagodkina OI, Stepanova MV (2015)
Problems with mapping the auroral oval and magnetospheric substorms.
Earth Planets Space 67:166. doi:10.1186/s40623‑015‑0336‑6
Berngardt OI, Zolotukhina NA, Oinats AV (2015) Observations of field‑aligned
ionospheric irregularities during quiet and disturbed conditions
with EKB radar: first results. Earth Planets Space 67:143. doi:10.1186/
s40623‑015‑0302‑3
Birn J, Liu Y, Daughton W, Hesse M, Schindler K (2015) Reconnection and inter‑change instability in the near magnetotail. Earth Planets Space 67:110.
doi:10.1186/s40623‑015‑0282‑3
Cherniak I, Zakharenkova I (2015) Dependence of the high‑latitude plasma
irregularities on the auroral activity indices: a case study of 17 March
2015 geomagnetic storm. Earth Planets Space 67:151. doi:10.1186/
s40623‑015‑0316‑x
Connors M, Rostoker G (2015) Inverting magnetic meridian data using
nonlinear optimization. Earth Planets Space 67:155. doi:10.1186/
s40623‑015‑0315‑yConnors M, Russell CT, Chu X, McPherron RL (2015) The February 24, 2010
substorm: a refined view involving a pseudobreakup/expansive phase/poleward boundary intensification sequence. Earth Planets Space 67:195.
doi:10.1186/s40623‑015‑0363‑3
Connors M, Schofield I, Reiter K, Chi PJ, Rowe KM, Russell CT (2016) The
AUTUMNX magnetometer meridian chain in Québec, Canada. Earth
Planets Space 68:2. doi:10.1186/s40623‑015‑0354‑4
Hajra R, Tsurutani BT, Echer E, Gonzalez WD, Brum CGM, Vieira LEA, Santolik
O (2015) Relativistic electron acceleration during HILDCAA events: areprecursor CIR magnetic storms important? Earth Planets Space 67:109.
doi:10.1186/s40623‑015‑0280‑52

Earth, Planets and Space

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Open Access

Relativistic electron acceleration during HILDCAA events: areprecursor CIR magnetic storms important?
Rajkumar Hajra*, Bruce T Tsurutani, Ezequiel Echer, Walter D Gonzalez,
Christiano Garnett Marques Brum, Luis Eduardo Antunes Vieira and Ondrej Santolik
Earth, Planets and Space 2015, 67:109 DOI: 10.1186/s40623-015-0280-5
Received: 21 June 2015, Accepted: 22 June 2015, Published: 7 July 2015

Abstract
We present a comparative study of high-intensity long-duration continuous AE activity (HILDCAA) events, both isolated and those occurringin the “recovery phase” of geomagnetic storms induced by corotating interaction regions (CIRs). The aim of this study is to determine thedifference, if any, in relativistic electron acceleration and magnetospheric energy deposition. All HILDCAA events in solar cycle 23 (from 1995
through 2008) are used in this study. Isolated HILDCAA events are characterized by enhanced fluxes of relativistic electrons compared to thepre-event flux levels. CIR magnetic storms followed by HILDCAA events show almost the same relativistic electron signatures. Cluster 1
spacecraft showed the presence of intense whistler-mode chorus waves in the outer magnetosphere during all HILDCAA intervals (whenCluster data were available). The storm-related HILDCAA events are characterized by slightly lower solar wind input energy and larger
magnetospheric/ionospheric dissipation energy compared with the isolated events. A
quantitative assessment shows that the mean ring current dissipation is ~34 % higher for thestorm-related events relative to the isolated events, whereas Joule heating and auroral
precipitation display no (statistically) distinguishable differences. On the average, the isolated
events are found to be comparatively weaker and shorter than the storm-related events,
although the geomagnetic characteristics of both classes of events bear no statisticallysignificant difference. It is concluded that the CIR storms preceding the HILDCAAs have little to
do with the acceleration of relativistic electrons. Our hypothesis is that ~10–100-keV electrons
are sporadically injected into the magnetosphere during HILDCAA events, the anisotropic
electrons continuously generate electromagnetic chorus plasma waves, and the chorus thencontinuously accelerates the high-energy portion of this electron spectrum to MeV energies.

Keywords: HILDCAAs; High-speed streams; CIRs; Chorus plasma waves; Radiation belt;
Magnetospheric relativistic electrons; Solar wind; Geomagnetic storms

Figure 1*Corresponding author: Rajkumar Hajra, rajkumarhajra@yahoo.co.in

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Open Access

Further evidence for the role of magnetotail current shape insubstorm initiation
M. Kubyshkina*, N. Tsyganenko, V. Semenov, D. Kubyshkina, N. Partamies and E. Gordeev
Earth, Planets and Space 2015, 67:139 DOI: 10.1186/s40623-015-0304-1
Received: 24 March 2015, Accepted: 11 August 2015, Published: 28 August 2015

Abstract
Substorm initiation still remains an unsolved problem, even though there is a consensus among most researchers that its
main stages include dayside reconnection and substorm expansion. Dayside reconnection results in magnetotail flux buildup
to a certain critical level, after which [or after the interplanetary magnetic field (IMF) Bz
turns northward] the substorm expansion begins. One problem with the above scenario isthat the critical amount of magnetic flux differs from one substorm to another, and notevery northward turning of the IMF Bz triggers a substorm. We suggest that an importantfactor in substorm dynamics may be the variable shape and alignment of themagnetospheric tail current sheet, which bends and warps in response to diurnal/seasonalchanges of the Earth’s dipole tilt angle and also in response to more rapid changes of thesolar wind flow direction. Both of these factors may be important, if one assumes that the
deformed current sheet becomes unstable at lower values of the tail lobe magnetic flux/pressure than the planar sheet. To investigate this idea, we examined large multi-year setsof THEMIS, Cluster, and Geotail data and established a relationship between the tail lobe Bx
and the dipole tilt angle. Further examinations of substorm events during 2005–2010
supported the hypothesis that their probability and intensity indeed depended on the
concurrent values of the tilt angle.

Keywords: Magnetospheric substorm; Tail current sheet; Empirical modeling
Figure 1*Corresponding author: M. Kubyshkina, kubysh@geo.phys.spbu.ru
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Open AccessInverting magnetic meridian data using nonlinear optimization
Martin Connors* and Gordon Rostoker
Earth, Planets and Space 2015, 67:155 DOI: 10.1186/s40623-015-0315-y
Received: 29 April 2015, Accepted: 27 August 2015, Published: 17 September 2015

Abstract
A nonlinear optimization algorithm coupled with a model of auroral current systems allows derivation of physical parametersfrom data and is the basis of a new inversion technique. We refer to this technique as automated forward modeling (AFM),
with the variant used here being automated meridian modeling (AMM). AFM is applicable on scales from regional to global,
yielding simple and easily understood output, and using only magnetic data with no assumptions about electrodynamic
parameters. We have found the most useful output parameters to be the total current and the boundaries of the auroralelectrojet on a meridian densely populated with magnetometers, as derived by AMM. Here, we describe application of AFM
nonlinear optimization to magnetic data and then describe the use of AMM to study substorms with magnetic data fromground meridian chains as input. AMM inversion results are compared to optical data, results from other inversion methods,
and field-aligned current data from AMPERE. AMM yields physical parameters
meaningful in describing local electrodynamics and is suitable for ongoing monitoringof activity. The relation of AMM model parameters to equivalent currents is discussed,
and the two are found to compare well if the field-aligned currents are far from theinversion meridian.

Keywords: Current systems; Substorms; Geophysical inversion techniques; Nonlinear
optimization; Geomagnetism; Equivalent current

Figure 1*Corresponding author: Martin Connors, martinc@athabascau.ca

FULL PAPER

Open AccessFull-particle simulations of instabilities in a thin current
sheet of the magnetospheric system prior to substorm onset
Hirotoshi Uchino* and Shinobu Machida
Earth, Planets and Space 2015, 67:165 DOI: 10.1186/s40623-015-0335-7
Received: 29 April 2015, Accepted: 23 September 2015, Published: 8 October 2015

Abstract
Substorm triggering was the focus of recent two-dimensional superposed-epoch analyses based on Geotail and THEMIS data.
The results indicate that magnetic-field dipolarization at X～−8 Re and magnetic reconnection at X～−20 Re occur
simultaneously at the onset. These results imply that there are physical mechanisms that widely affect both the dipole andcurrent-sheet regions. The analyses also have found that a local Bz enhancement appears before the substorm onset andmagnetic reconnection occurs at its tailward edge. We performed four 2.5-dimensional full-particle simulations with a new
initial magnetic-field structure to focus on instabilities in the magnetosphere. The structure is similar to the Earth’s dipole
magnetic field combined with a stretched field and current sheet on the tailward side. The simulation with the initial
magnetic-field configuration shows that nodes of the magnetic field appear in the current sheet where the growth conditionof tearing instability is satisfied. The features of the instability are close to those of the electron tearing mode reported inprevious simulation results. Another three simulations with a local Bz enhancement, as seen in the observational results, atvarious locations in the current sheet were performed to explore its impacts on the evolution of the instability. A relaxation
process around the enhancement generates a new node at its tailward
edge if its location satisfies the growth condition. The wavelength and(b)(c)
Particle Density
Magnetic Field Linedominant mode of the instability can be changed by the coupling between
the process and tearing mode depending on the location of theenhancement. Our simulations reveal new features associated with tearing
instabilities in the magnetospheric-field configuration.
28.48

15

15

21.36

10

Keywords: Tearing instability; Magnetospheric substorm; Magnetic
reconnection

z/d

z/d

10

5

0

-5

-5

0

-5

-10

x/d

-15

-20

-25

Figure 1*Corresponding author: Hirotoshi Uchino, uchino@kugi.kyoto-u.ac.jp
4

14.24

5

0

7.12
0.00

-5

-10

x/d

-15

-20

-25

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Open AccessPC index as a proxy of the solar wind energy that enteredinto the magnetosphere: 2. Relation to the interplanetary
electric field EKL before substorm onset
OA Troshichev* and DA Sormakov
Earth, Planets and Space 2015, 67:170 DOI: 10.1186/s40623-015-0338-4
Received: 2 April 2015, Accepted: 6 October 2015, Published: 21 October 2015

Abstract
This paper (the second of a series) presents the results of statistical investigation of relationship between the interplanetary electricfield EKL and the Polar Cap (PC) index in case of magnetic substorms (1998–2001), which have been
analyzed in Troshichev et al. (J. Geophys. Res. Space Physics, 119, 2014). The PC index is directly related
to the EKL field variations on interval preceding the substorm sudden onset (SO): correlation R > 0.5 istypical of more than 90 % of isolated substorms, 80 % of expanded substorms, and 99 % of events withcoordinated EKL and PC jumps. The low or negative correlation observing in ~10 % of examined
substorms suggests that the solar wind flow measured by the Advanced Composition Explorer (ACE)spacecraft in the Lagrange point L1 did not encounter the magnetosphere in these cases. Examinationof the delay times ΔT in the response of PC index to EKL variations provides the following results: (1)delay times do not depend on separate solar wind parameters, such as solar wind speed VX andinterplanetary magnetic field (IMF) BZ component, contrary to general conviction, (2) the ΔT value isbest controlled by the EKL field growth rate (dEKL/dt), (3) the lower ΔT limit (5–7 min is attained underconditions of the higher EKL growth rate, and (4) the PC index provides the possibility to verify the solar
wind flow transportation time from ACE position (where the solar wind speed is estimated) tomagnetosphere. These results, in combination with data testifying that the substorm onsets are related
to the PC precursors, demonstrate that the PC index is an adequate ground-based indicator of the solar
wind energy incoming into the magnetosphere.

Keywords: Interplanetary electric field EKL; PC index; Magnetic substorms; Delay time; Solar windparameters growth rate; Solar wind energy input

Figure 1*Corresponding author: OA Troshichev, olegtro@aari.ru

FULL PAPER

Open Access

Eastward-expanding auroral surges observed in the post-midnight
sector during a multiple-onset substorm
Yoshimasa Tanaka*, Yasunobu Ogawa, Akira Kadokura, Noora Partamies, Daniel Whiter,
Carl-Fredrik Enell, Urban Brändström, Tima Sergienko, Björn Gustavsson, Alexander Kozlovsky,
Hiroshi Miyaoka and Akimasa Yoshikawa
Earth, Planets and Space 2015, 67:182 DOI: 10.1186/s40623-015-0350-8
Received: 30 April 2015, Accepted: 28 October 2015, Published: 9 November 2015

Abstract
We present three eastward-expanding auroral surge (EEAS) events that were observed intermittently at intervals of about 15 min in the
post-midnight sector (01:55–02:40 MLT) by all-sky imagers and magnetometers in northern Europe. It was deduced that each surge occurredjust after each onset of a multiple-onset substorm, which was small-scale and did not clearly expand
westward, because they were observed almost simultaneously with Pi 2 pulsations at the magnetic
equator and magnetic bay variations at middle-to-high latitudes associated with the DP-1 current
system. The EEASs showed similar properties to omega bands or torches reported in previous studies,such as recurrence intervals of about 15 min, concurrence with magnetic pulsations with amplitudes ofseveral tens of nanotesla, horizontal scales of 300–400 km, and occurrence of a pulsating aurora in adiffuse aurora after the passage of the EEASs. Furthermore, the EEASs showed similar temporal evolution
to the omega bands, during which eastward-propagating auroral streamers occurred simultaneously inthe poleward region, followed by the formation of north-south-aligned auroras, which eventuallyconnected with the EEASs. Thus, we speculate that EEASs may be related to the generation process ofomega bands. On the other hand, the EEASs we observed had several properties that were different fromthose of omega bands, such as greater eastward propagation speed (3–4 km/s), shorter associatedmagnetic pulsation periods (4–6 min), and a different ionospheric equivalent current direction. The fasteastward propagation speed of the EEASs is consistent with the speed of eastward expansion fronts ofthe substorm current wedge reported in previous studies. The difference in the ionospheric current
between the EEASs and omega bands may be caused by a large temporal variation of the surge
structure, compared with the more stable wavy structure of omega bands.

Keywords: Eastward-expanding auroral surges; Auroral streamers; Post-midnight sector; Substorm
expansion phase; Omega bands; Magnetic pulsations; Ionospheric equivalent current*Corresponding author: Yoshimasa Tanaka, ytanaka@nipr.ac.jp
5Figure 1

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Open Access

The February 24, 2010 substorm: a refined view involving
a pseudobreakup/expansive phase/poleward boundary
intensification sequence
Martin Connors*, Christopher T. Russell, Xiangning Chu and Robert L. McPherron
Earth, Planets and Space 2015, 67:195 DOI: 10.1186/s40623-015-0363-3
Received: 1 May 2015, Accepted: 9 November 2015, Published: 3 December 2015

Abstract
A substorm on February 24, 2010 was chosen for study by Connors et al. (Geophys. Res. Lett. 41:4449–4455, 2014) due to simple symmetricsubauroral magnetic perturbations observed in North America. It was shown that a substorm current wedge (SCW) three-dimensional current
model could represent these perturbations well, gave a reasonable representation of auroral zone perturbations, and matched field-aligned
currents determined in space from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) project. The
conclusion was that substorm onset was at approximately 4:30 UT and that the substorm current
wedge (SCW) formed in the region 1 (more poleward) current system.
Here, we examine the substorm in more detail, using ground optical data, more ground magnetic
measurements, and in-situ measurements in the region of the substorm downward current by
three Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecrafts.
We apply magnetic inversion techniques and find that they agree with and complement optical
data. We find that a sequence involving three previously categorized types of substorm-related
response took place, that is, a pseudobreakup or weak expansive phase, followed by the full onsetof a substorm expansive phase (EP), and in turn by a poleward boundary intensification (PBI)
carrying the bulk of the SCW current. The initial activity was equatorward of that described by
Connors et al. (Geophys. Res. Lett. 41:4449–4455, 2014) and began at 4:11 UT. The THEMIS
spacecraft in the early morning sector detected magnetic field changes associated with the EP and
PBI, aiding in differentiating them. The fuller picture suggests involvement of regions both
relatively near the Earth and deeper in the magnetotail, in the overall substorm process.
OMNI BZ C1 BX BY BZ

4

nT

2
0

−2
−4

03:00

nT

100
0
−100
−200
−300
−400
−500
−600

03:30

04:00

04:30

05:00

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04:00
04:30
05:00
UT February 24 2010

05:30

06:00

AL AU THEMIS AL BLC BX Nuuk BX

03:00

03:30

Midlatitude B Components
Northward Eastward

40

30

nT

20
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−20

−30

−40

Keywords: Substorms; Pseudobreakups; Expansive phase; Poleward boundary intensifications;

HOTS (Montana)
3

4

5

DRBY (Vermont)

SWNO (Illinois)
6

Data inversion

3

4
5
6
UT February 24 2010

3

4

5

6

Figure 1*Corresponding author: Martin Connors, martinc@athabascau.ca

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Open Access

The AUTUMNX magnetometer meridian chain in Québec,CanadaMartin Connors*, Ian Schofield, Kyle Reiter, Peter J. Chi, Kathryn M. Rowe and Christopher T. Russell
Earth, Planets and Space 2016, 68:2 DOI: 10.1186/s40623-015-0354-4
Received: 6 May 2015, Accepted: 4 November 2015, Published: 7 January 2016

Abstract

20

˚

˚
60

Inuvik

0˚

5

−1

72

−1

˚

−1

68

˚
64

˚

50

−1

35
˚

˚

The AUTUMNX magnetometer array consists of 10 THEMIS-class ground-based magnetometers deployed to form a meridian
chain on the eastern coast of Hudson Bay in eastern Canada, a second partial chain one hour of magnetic local time further
east, and one magnetometer at an intermediate midlatitude site. These instruments,
augmented by those of other arrays, permit good latitudinal coverage through theauroral zone on two meridians, some midlatitude coverage, and detection ofmagnetic field changes near the sensitive infrastructure of the Hydro-Québec power
grid. Further, they offer the possibility for conjugate studies with Antarctica and the
GOES East geosynchronous satellite, and complement the Chinese International
Space Weather Meridian Circle Program. We examine current world distribution ofmagnetometers to show the need for AUTUMNX, and describe the instrumentation
which allows near-real-time monitoring. We present magnetic inversion results forthe disturbed day February 17, 2015, which showed classic signatures of thesubstorm current wedge, and developed into steady magnetospheric convection(SMC). For a separate event later that day, we examine a large and rapid magnetic
field change event associated with an unusual near-Earth transient. We show GOES
East conjugacy for these events.

72˚Whitehorse

68˚

˚

56

64˚

35

˚

52

−1

˚

Fort St John

60˚

Athabasca48

˚

La Ronge

56˚

Red DeerCalgary

Saskatoon

Figure 1*Corresponding author: Martin Connors, martinc@athabascau.ca
6

52˚

˚

48˚

−105

˚

−1

currents; Substorm; Electrojet; Data inversion

44

20

Keywords: Geomagnetism; Geophysical instrumentation; Geomagnetically induced

˚

Lethbridge

Earth, Planets and Space

FULL PAPER

Open Access

Latitudinal dependence on the frequency of Pi2 pulsations near theplasmapause using THEMIS satellites and Asian-OceanianSuperDARN radars
Mariko Teramoto*, Nozomu Nishitani, Yukitoshi Nishimura and Tsutomu Nagatsuma
Earth, Planets and Space 2016, 68:22 DOI: 10.1186/s40623-016-0397-1
Received: 13 May 2015, Accepted: 10 January 2016, Published: 17 February 2016

Abstract
We herein describe a harmonic Pi2 wave that started at 09:12 UT on August 19, 2010, with data that were obtained simultaneously at
19:00–20:00 MLT by three mid-latitude Asian-Oceanian Super Dual Auroral Radar Network (SuperDARN) radars (Unwin, Tiger, andHokkaido radars), three Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites (THEMIS A, THEMIS
D, and THEMIS E), and ground-based magnetometers at low and high latitudes. All THEMIS satellites, which were located in theplasmasphere, observed Pi2 pulsations dominantly in the magnetic compressional (B//) and electric azimuthal (EA) components, i.e.,
the fast-mode component. The spectrum of Pi2 pulsations in the B// and EA components contained two spectral peaks at
approximately 12 to 14 mHz (f1, fundamental) and 23 to 25 mHz (f2, second harmonic). The Poynting flux derived from the electric andmagnetic fields indicated that these pulsations were waves propagating earthward and duskward. Doppler variations (V) from the 6-s
or 8-s resolution camping beams of the Tiger and Unwin SuperDARN radars, which areassociated with Pi2 pulsations in the eastward electric field component in the ionosphere,
observed Pi2 pulsations within and near the footprint of the plasmapause, whose location
was estimated by the THEMIS satellites. The latitudinal profile of f2 power normalized by f1
power for Doppler velocities indicated that the enhancement of the normalized f2 power
was the largest near the plasmapause at an altitude-adjusted corrected geomagnetic(AACGM) latitude of 60° to 65°. Based on these features, we suggest that compressional
waves propagate duskward away from the midnight sector, where the harmonic cavity
mode is generated.
16hMLT

PTK

18hMLT

DRV

STC

MMB

THD

THE

MCQ

THA

TIG

THD
THE
THA

20

hM

UNW

LT

hM

22

LT

SuperDARN radars; THEMIS satellites

24hM

Keywords: Pi2 pulsations near the plasmapause; Multipoint observations; Mid-latitudeLT

Figure 1*Corresponding author: Mariko Teramoto, teramoto@stp.isas.jaxa.jp

LETTER

Open Access

Reconnection flow jets in 3D as a source of structured
dipolarization fronts
Philip L. Pritchett
Earth, Planets and Space 2015, 67:103 DOI: 10.1186/s40623-015-0264-5
Received: 18 March 2015, Accepted: 5 June 2015, Published: 27 June 2015

Abstract
Three-dimensional electromagnetic particle-in-cell simulations are used to investigate the propagation and breakup of areconnection flow jet of initial cross-tail extent 24di (～1.5RE; di is the ion inertial length). Such a front is found to separate into
two segments, with the dawnward portion propagating ahead of the duskward one. Both segments expand duskward,
reaching separate lengths of 18–25di, and both segments develop internal structures on east–west scales of 1–2di. The
currents responsible for the ramp up of Bz at the fronts are confined to narrow (＜～ di) ribbons whose localization is primarily
associated with the electron Uey flow. The incoming ion flow is slowed down and deflected duskward at the front, and ambientions are reflected back from the moving front. These processes create regions of enhanced Tixx both downstream andupstream of the front, while there is a local minimum at the front itself. These results help to explain the prevalence of ～1RE
flow jets in the plasma sheet.

Keywords: Localized magnetic reconnection; Dipolarization front;

Reconnection jet breakup; Ballooning/interchange mode; 3D
PIC simulation; Ion temperature asymmetries

Figure 1

Corresponding author: Philip L. Pritchett, pritchet@physics.ucla.edu
7

The 12th International Conference on Substorms

LETTER

Open Access

Reconnection and interchange instability in the near magnetotail
Joachim Birn*, Yi-Hsin Liu, William Daughton, Michael Hesse and Karl Schindler
Earth, Planets and Space 2015, 67:110 DOI: 10.1186/s40623-015-0282-3
Received: 1 May 2015, Accepted: 25 June 2015, Published: 16 July 2015

Abstract
This paper provides insights into the possible coupling between reconnection and interchange/ballooning in the magnetotail
related to substorms and flow bursts. The results presented are largely based on recent simulations of magnetotail dynamics,
exploring onset and progression of reconnection. 2.5-dimensional particle-in-cell (PIC) simulations with different taildeformation demonstrate a clear boundary between stable and unstable cases depending on the amount of deformation,
explored up to the real proton/electron mass ratio. The evolution prior to onset, as well as the evolution of stable cases, aregoverned by the conservation of integral flux tube entropy S as imposed in ideal MHD, maintaining a monotonic increase with
distance downtail. This suggests that ballooning instability in the tail should not be expected prior to the onset of tearing andreconnection. 3-D MHD simulations confirm this conclusion, showing no indication of ballooning prior to reconnection, if theinitial state is ballooning stable. The simulation also shows that, after imposing resistivity necessary to initiate reconnection,
the reconnection rate and energy release initially remain slow. However, when S becomes reduced from plasmoid ejection
and lobe reconnection, forming a negative slope in S as a function of distance from Earth, the reconnection rate and energy
release increase drastically. The latter condition has been shown to be necessary for ballooning/interchange instability, andthe cross-tail structures that develop subsequently in the MHD simulation are consistent with such modes. The simulations
support a concept in which tail activity is initiated by tearing instability but significantly enhanced by the interaction withballooning/interchange enabled by plasmoid loss
and lobe reconnection.

Keywords: Reconnection; Interchange; Magnetotail
dynamics; Substorms

Figure 1*Corresponding author: Joachim Birn, jbirn@spacescience.org

LETTER

Open AccessOn the plasma sheet dependence on solar wind and substorms
and its role in magnetosphere-ionosphere coupling
V A Sergeev*, N P Dmitrieva, N A Stepanov, D A Sormakov, V Angelopoulos and A V RunovEarth, Planets and Space 2015, 67:133 DOI: 10.1186/s40623-015-0296-x
Received: 26 March 2015, Accepted: 24 July 2015, Published: 19 August 2015

Abstract
Recently, it was argued that Hall conductivity and peak intensity of equivalent ionospheric currents are sensitive to the amount offield-aligned acceleration of plasma sheet (PS) electrons, which in turn depends on the plasma sheet parameters Te and Ne (electron
temperature and density) proportionally to the quantity eTN = (Te)1/2/Ne. Here we extend these studies using data from six tail seasonsof THEMIS observations to show statistically that the behavior of these PS electron
parameters, measured in the middle of the nightside plasma sheet at ~10 RE distance,
depends in a very different way on two basic processes: the solar wind state and substorms.
We confirm previous work that slow/dense (fast/tenuous) solar wind provides cold/dense(hot/tenuous) plasma sheet conditions. However, we find that electron temperature andpressure parameters (Te and Pe) behave differently from the proton ones (Tp and Pp),
indicating a strong decoupling between temperature variations of auroral protons andelectrons in the central plasma sheet (CPS): electrons are more sensitive to the substormrelated acceleration in the magnetotail than protons. Our superposed epoch study ofplasma sheet parameter variations during substorms as well as our analysis of plasma
acceleration at dipolarization fronts shows that during the substorm expansion phase anew (accelerated and plasma-depleted) population comes into the inner CPS with the flow
bursts, showing an average increase of electron temperature and eTN parameter roughly bya factor of 2 above its background values for both cold/dense and hot/tenuous plasma
sheet states. Preferential electron heating in the flow bursts is also statistically confirmed.

Keywords: Plasma sheet; Particle acceleration; Solar wind driver; Substorms; Flow burst*Corresponding author: V A Sergeev, victor@geo.phys.spbu.ru
8

Figure 1

Earth, Planets and SpaceLETTER

Open AccessObservations of field-aligned ionospheric irregularities during quiet
and disturbed conditions with EKB radar: first results
Oleg I. Berngardt*, Nina A. Zolotukhina and Alexey V. Oinats
Earth, Planets and Space 2015, 67:143 DOI: 10.1186/s40623-015-0302-3
Received: 30 April 2015, Accepted: 10 August 2015, Published: 3 September 2015

Abstract
This paper presents the first results of statistical analysis of 2-year data series obtained with the first midlatitude decameter
coherent radar of Russian segment of SuperDARN network. Based on individual events observed on 13–15 December 2013
and 1–4 January 2014, we also demonstrate the possibility ofusing the radar data for monitoring of magnetosphereionosphere dynamics in quiet and disturbed geomagnetic
conditions.

Keywords: Midlatitude SuperDARN radar; Dynamics offield-aligned ionospheric irregularities;
Substorm-like events

Figure 1*Corresponding author: Oleg I. Berngardt, berng@iszf.irk.ru

LETTER

Open Access

The problem of the acceleration of electrons of the outerradiation belt and magnetospheric substorms
E. E. Antonova* and M. V. Stepanova
Earth, Planets and Space 2015, 67:148 DOI: 10.1186/s40623-015-0319-7
Received: 1 May 2015, Accepted: 28 August 2015, Published: 15 September 2015

Abstract

PC

AL,A U, nT

SYM-H, nT

Predicting of the location of the maximum in high-energy electron fluxes filling a new radiation belt is an endeavor being
carried out by physicists studying the magnetosphere. We analyzed the data from the Defense Meteorological Satellite
Program (DMSP) satellites and ground-based magnetometers obtained during geomagnetic storm on 8–9 October 2012. The
minimum value of the disturbance storm time (Dst) was −111 nT, and the maximum in high-energy electron fluxes thatappeared during the recovery phase was observed at L = 4 Re. At the same time, we analyzed the motion of the auroral oval
toward lower latitudes and related substorm activity using the data of the low-orbiting DMSP satellites and the IMAGE
magnetic meridian network. It was found from the DMSP satellites’ measurements that the maximum of the energy density of
precipitating ions, the maximum of the plasma pressure, and the most equatorial(c)part of the westward auroral electrojet are all located at the 60° geomagnetic
0
latitude. This value corresponds to L = 4 Re, i.e., it coincides with the location of the
50
100
maximum in high-energy electron fluxes. This L-value also agrees with thepredictions of the Tverskaya relation between the minimum in Dst variation and the
500
0location of the maximum of the energetic electron fluxes, filling a new radiation belt.
500
The obtained results show that the location of this maximum could be predicted
1000
1500
solely from the data of the auroral particle precipitations and/or ground-based
10
magnetic observations.

Keywords: Magnetospheric storm and substorm; Outer radiation belt; Auroral oval

5

0
281

282

283

DOY

Figure 1*Corresponding author: E. E. Antonova, antonova@orearm.msk.ru
9

284

285

286

The 12th International Conference on Substorms

LETTER

Open Access

Dependence of the high-latitude plasma irregularities on the auroral
activity indices: a case study of 17 March 2015 geomagneticstorm
Iurii Cherniak* and Irina Zakharenkova
Earth, Planets and Space 2015, 67:151 DOI: 10.1186/s40623-015-0316-x
Received: 2 May 2015, Accepted: 27 August 2015, Published: 15 September 2015

Bz (nT)

20
10
0
-10
-20

Bx (nT)

20
10
0
-10
-20
20
10
0
-10
-20

Vsw (km/s)

Np, cm-3

50
40
30
20
10
0
700
600
500
400

Psw (nPa)300

SYM-H (nT)The magnetosphere substorm plays a crucial role in the solar wind energy dissipation into
the ionosphere. We report on the intensity of the high-latitude ionospheric irregularities
during one of the largest storms of the current solar cycle—the St. Patrick’s Day storm of 17
March 2015. The database of more than 2500 ground-based Global Positioning System(GPS) receivers was used to estimate the irregularities occurrence and dynamics over theauroral region of the Northern Hemisphere. We analyze the dependence of the GPSdetected ionospheric irregularities on the auroral activity. The development and intensity of
the high-latitude irregularities during this geomagnetic storm reveal a high correlation withthe auroral hemispheric power and auroral electrojet indices (0.84 and 0.79, respectively).
Besides the ionospheric irregularities caused by particle precipitation inside the polar cap
region, evidences of other irregularities related to the storm enhanced density (SED),
formed at mid-latitudes and its further transportation in the form of tongue of ionization(TOI) towards and across the polar cap, are presented. We highlight the importanceaccounting contribution of ionospheric irregularities not directly related with particle
precipitation in overall irregularities distribution and intensity.

By (nT)

Abstract

25
20
15
10
5
0
50
-50

-150

Keywords: Ionosphere irregularities; Geomagnetic storm; Auroral hemispheric power-250

index; Auroral precipitation; GPS; ROTI

15

16

SSC 1718

19

20

Figure 1*Corresponding author: Iurii Cherniak, tcherniak@ukr.net

LETTER

Open Access

Problems with mapping the auroral oval andmagnetospheric substorms
E. E. Antonova*, V. G. Vorobjev, I. P. Kirpichev, O. I. Yagodkina and M. V. Stepanova
Earth, Planets and Space 2015, 67:166 DOI: 10.1186/s40623-015-0336-6
Received: 30 April 2015, Accepted: 1 October 2015, Published: 12 October 2015

Abstract
Accurate mapping of the auroral oval into the equatorial plane is critical for the analysis of aurora and substorm dynamics.
Comparison of ion pressure values measured at low altitudes by Defense Meteorological Satellite Program (DMSP) satellites
during their crossings of the auroral oval, with plasma pressure values obtained at the equatorial plane from Time History of
Events and Macroscale Interactions during Substorms (THEMIS) satellite measurements, indicates that the main part of theauroral oval maps into the equatorial plane at distances between 6 and 12 Earth radii. On the nightside, this region is generally
considered to be a part of the plasma sheet. However, our studies suggest that this region could form part of the plasma ringsurrounding the Earth. We discuss the possibility ofusing the results found here to explain the ring-likeshape of the auroral oval, the location of the injection
boundary inside the magnetosphere near thegeostationary orbit, presence of quiet auroral arcs inthe auroral oval despite the constantly high level of
turbulence observed in the plasma sheet, and somefeatures of the onset of substorm expansion.

Figure 1*Corresponding author: E. E. Antonova, antonova@orearm.msk.ru
10

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Contents
Special issue “The 12th International Conference on Substorms” . . . . . . . . Kazuo Shiokawa, Mei-Ching Fok and Masaki Fujimoto
Relativistic electron acceleration during HILDCAA events: are precursor CIR magnetic storms important?
. . . . . . . . . . . . . . . . . . . . . . . . . . . . Rajkumar Hajra, Bruce T Tsurutani, Ezequiel Echer, Walter D Gonzalez, Christiano Garnett Marques Brum,Luis Eduardo Antunes Vieira and Ondrej Santolik

Further evidence for the role of magnetotail current shape in substorm initiation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. Kubyshkina, N. Tsyganenko, V. Semenov, D. Kubyshkina, N. Partamies and E. Gordeev
Inverting magnetic meridian data using nonlinear optimization . . . . . . . . . . . . . . . . . . . . . . . . . . Martin Connors and Gordon Rostoker
Full-particle simulations of instabilities in a thin current sheet of the magnetospheric system prior to substorm onset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hirotoshi Uchino and Shinobu Machida
PC index as a proxy of the solar wind energy that entered into the magnetosphere: 2. Relation to the interplanetary
electric field EKL before substorm onset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OA Troshichev and DA Sormakov
Eastward-expanding auroral surges observed in the post-midnight sector during a multiple-onset substorm. . . . . . Yoshimasa Tanaka, Yasunobu Ogawa, Akira Kadokura, Noora Partamies, Daniel Whiter, Carl-Fredrik Enell, Urban Brändström,
Tima Sergienko, Björn Gustavsson, Alexander Kozlovsky, Hiroshi Miyaoka and Akimasa Yoshikawa

1

3
3
4
4
5

5

The February 24, 2010 substorm: a refined view involving a pseudobreakup/expansive phase/poleward boundary
intensification sequence . . . . . . . . . . . . . . . . . . . . . . . . Martin Connors, Christopher T. Russell, Xiangning Chu and Robert L. McPherron 6
The AUTUMNX magnetometer meridian chain in Québec, Canada. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Martin Connors, Ian Schofield, Kyle Reiter, Peter J. Chi, Kathryn M. Rowe and Christopher T. Russell 6
Latitudinal dependence on the frequency of Pi2 pulsations near the plasmapause using THEMIS satellites andAsian-Oceanian SuperDARN radars . . . . . . . . Mariko Teramoto, Nozomu Nishitani, Yukitoshi Nishimura and Tsutomu Nagatsuma 7
Reconnection flow jets in 3D as a source of structured dipolarization fronts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Philip L. Pritchett 7
Reconnection and interchange instability in the near magnetotail. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Joachim Birn, Yi-Hsin Liu, William Daughton, Michael Hesse and Karl Schindler 8
On the plasma sheet dependence on solar wind and substorms and its role in magnetosphere-ionosphere coupling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V A Sergeev, N P Dmitrieva, N A Stepanov, D A Sormakov, V Angelopoulos and A V Runov 8
Observations of field-aligned ionospheric irregularities during quiet and disturbed conditions with EKB radar:first results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oleg I. Berngardt, Nina A. Zolotukhina and Alexey V. Oinats 9
The problem of the acceleration of electrons of the outer radiation belt and magnetospheric substorms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. E. Antonova and M. V. Stepanova 9
Dependence of the high-latitude plasma irregularities on the auroral activity indices: a case study of 17 March 2015
geomagnetic storm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Iurii Cherniak and Irina Zakharenkova 10
Problems with mapping the auroral oval and magnetospheric substorms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. E. Antonova, V. G. Vorobjev, I. P. Kirpichev, O. I. Yagodkina and M. V. Stepanova 10

Cover image: Tanaka, Y. et al., Earth, Planets and Space 2015, 67:182 DOI: 10.1186/s40623-015-0350-8