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Journal of Geophysical Research. Space Physics

X Shi, J M Ruohoniemi, J B H Baker, D Lin, E C Bland, M D Hartinger, W A Scales
Ionospheric signatures of ultra-low frequency (ULF) wave in the Pc3-5 band (1.7-40.0 mHz) were surveyed using ~6 s resolution data from Super Dual Auroral Radar Network (SuperDARN) radars in the northern hemisphere from 2010 to 2016. Numerical experiments were conducted to derive wave period dependent thresholds for automated detection of ULF waves using the Lomb-Scargle periodogram technique. The spatial occurrence distribution, frequency characteristics, seasonal effects, solar wind condition and geomagnetic activity level dependence have been studied...
May 2018: Journal of Geophysical Research. Space Physics
E Astafyeva, I Zakharenkova, K Hozumi, P Alken, P Coïsson, M R Hairston, W R Coley
We use a set of ground-based instruments (Global Positioning System receivers, ionosondes, magnetometers) along with data of multiple satellite missions (Swarm, C/NOFS, DMSP, GUVI) to analyze the equatorial and low-latitude electrodynamic and ionospheric disturbances caused by the geomagnetic storm of 22-23 June 2015, which is the second largest storm in the current solar cycle. Our results show that at the beginning of the storm, the equatorial electrojet (EEJ) and the equatorial zonal electric fields were largely impacted by the prompt penetration electric fields (PPEF)...
March 2018: Journal of Geophysical Research. Space Physics
Stefan J Hofmeister, Astrid Veronig, Manuela Temmer, Susanne Vennerstrom, Bernd Heber, Bojan Vršnak
We study the properties of 115 coronal holes in the time range from August 2010 to March 2017, the peak velocities of the corresponding high-speed streams as measured in the ecliptic at 1 AU, and the corresponding changes of the Kp index as marker of their geoeffectiveness. We find that the peak velocities of high-speed streams depend strongly on both the areas and the co-latitudes of their solar source coronal holes with regard to the heliospheric latitude of the satellites. Therefore, the co-latitude of their source coronal hole is an important parameter for the prediction of the high-speed stream properties near the Earth...
March 2018: Journal of Geophysical Research. Space Physics
S A Kiehas, A Runov, V Angelopolos, H Hietala, D Korovinksiy
As a direct result of magnetic reconnection, plasma sheet fast flows act as primary transporter of mass, flux, and energy in the Earth's magnetotail. During the last decades, these flows were mainly studied within X GSM >-60 R E , as observations near or beyond lunar orbit were limited. By using 5 years (2011-2015) of ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moons Interaction with the Sun) data, we statistically investigate earthward and tailward flows at around 60  R E downtail...
March 2018: Journal of Geophysical Research. Space Physics
Rumi Nakamura, Ali Varsani, Kevin J Genestreti, Olivier Le Contel, Takuma Nakamura, Wolfgang Baumjohann, Tsugunobu Nagai, Anton Artemyev, Joachim Birn, Victor A Sergeev, Sergey Apatenkov, Robert E Ergun, Stephen A Fuselier, Daniel J Gershman, Barbara J Giles, Yuri V Khotyaintsev, Per-Arne Lindqvist, Werner Magnes, Barry Mauk, Anatoli Petrukovich, Christopher T Russell, Julia Stawarz, Robert J Strangeway, Brian Anderson, James L Burch, Ken R Bromund, Ian Cohen, David Fischer, Allison Jaynes, Laurence Kepko, Guan Le, Ferdinand Plaschke, Geoff Reeves, Howard J Singer, James A Slavin, Roy B Torbert, Drew L Turner
We present characteristics of current layers in the off-equatorial near-Earth plasma sheet boundary observed with high time-resolution measurements from the Magnetospheric Multiscale mission during an intense substorm associated with multiple dipolarizations. The four Magnetospheric Multiscale spacecraft, separated by distances of about 50 km, were located in the southern hemisphere in the dusk portion of a substorm current wedge. They observed fast flow disturbances (up to about 500 km/s), most intense in the dawn-dusk direction...
February 2018: Journal of Geophysical Research. Space Physics
J L Burch, J M Webster, K J Genestreti, R B Torbert, B L Giles, S A Fuselier, J C Dorelli, A C Rager, T D Phan, R C Allen, L-J Chen, S Wang, O Le Contel, C T Russell, R J Strangeway, R E Ergun, A N Jaynes, P-A Lindqvist, D B Graham, F D Wilder, K-J Hwang, J Goldstein
This paper reports on Magnetospheric Multiscale observations of whistler mode chorus and higher-frequency electrostatic waves near and within a reconnection diffusion region on 23 November 2016. The diffusion region is bounded by crescent-shaped electron distributions and associated dissipation just upstream of the X-line and by magnetic field-aligned currents and electric fields leading to dissipation near the electron stagnation point. Measurements were made southward of the X-line as determined by southward directed ion and electron jets...
February 2018: Journal of Geophysical Research. Space Physics
E Astafyeva, I Zakharenkova, J D Huba, E Doornbos, J van den IJssel
By using data from multiple instruments, we investigate ionospheric/thermospheric behavior during the period from 21 to 23 June 2015, when three interplanetary shocks (IS) of different intensities arrived at Earth. The first IS was registered at 16:45 UT on 21 June and caused ~50 nT increase in the SYM-H index. The second IS arrived at 5:45 UT on 22 June and induced an enhancement of the auroral/substorm activity that led to rapid increase of thermospheric neutral mass density and ionospheric vertical total electron content at high latitudes...
November 2017: Journal of Geophysical Research. Space Physics
A Varsani, R Nakamura, V A Sergeev, W Baumjohann, C J Owen, A A Petrukovich, Z Yao, T K M Nakamura, M V Kubyshkina, T Sotirelis, J L Burch, K J Genestreti, Z Vörös, M Andriopoulou, D J Gershman, L A Avanov, W Magnes, C T Russell, F Plaschke, Y V Khotyaintsev, B L Giles, V N Coffey, J C Dorelli, R J Strangeway, R B Torbert, P-A Lindqvist, R Ergun
During a magnetic storm on 23 June 2015, several very intense substorms took place, with signatures observed by multiple spacecraft including DMSP and Magnetospheric Multiscale (MMS). At the time of interest, DMSP F18 crossed inbound through a poleward expanding auroral bulge boundary at 23.5 h magnetic local time (MLT), while MMS was located duskward of 22 h MLT during an inward crossing of the expanding plasma sheet boundary. The two spacecraft observed a consistent set of signatures as they simultaneously crossed the reconnection separatrix layer during this very intense reconnection event...
November 2017: Journal of Geophysical Research. Space Physics
R T Desai, M M Cowee, H Wei, X Fu, S P Gary, M Volwerk, A J Coates
In the vicinity of Europa, Galileo observed bursty Alfvén-cyclotron wave power at the gyrofrequencies of a number of species including K+ , O 2+, Na+ , and Cl+ , indicating the localized pickup of these species. Additional evidence for the presence of chlorine was the occurrence of both left-hand (LH) and right-hand (RH) polarized transverse wave power near the Cl+ gyrofrequency, thought to be due to the pickup of both Cl+ and the easily formed chlorine anion, Cl- . To test this hypothesis, we use one-dimensional hybrid (kinetic ion, massless fluid electron) simulations for both positive and negative pickup ions and self-consistently reproduce the growth of both LH and RH Alfvén-cyclotron waves in agreement with linear theory...
October 2017: Journal of Geophysical Research. Space Physics
Philip A Fernandes, Brian A Larsen, Michelle F Thomsen, Ruth M Skoug, Geoffrey D Reeves, Michael H Denton, Reinhard H W Friedel, Herbert O Funsten, Jerry Goldstein, Michael G Henderson, Jörg-Micha Jahn, Elizabeth A MacDonald, David K Olson
The two full precessions in local time completed by the Van Allen Probes enable global specification of the near-equatorial inner magnetosphere plasma environment. Observations by the Helium-Oxygen-Proton-Electron (HOPE) mass spectrometers provide detailed insight into the global spatial distribution of electrons, H+ , He+ , and O+ . Near-equatorial omnidirectional fluxes and abundance ratios at energies 0.1-30 keV are presented for 2 ≤ L ≤ 6 as a function of L shell, magnetic local time (MLT), and geomagnetic activity...
September 2017: Journal of Geophysical Research. Space Physics
Liam M Kilcommons, Robert J Redmon, Delores J Knipp
We have developed a method for reprocessing the multi-decadal, multi-spacecraft Defense Meteorological Satellite Program Magnetometer (DMSP SSM) dataset and have applied it to fifteen spacecraft-years of data (DMSP Flight 16-18, 2010-2014). This Level-2 dataset improves on other available SSM datasets with recalculated spacecraft locations and magnetic perturbations, artifact signal removal, representations of the observations in geomagnetic coordinates, and in-situ auroral boundaries. Spacecraft locations have been recalculated using ground-tracking information...
August 2017: Journal of Geophysical Research. Space Physics
Robert J Redmon, William F Denig, Liam M Kilcommons, Delores J Knipp
Since the mid 1970's, the Defense Meteorological Satellite Program (DMSP) spacecraft have operated instruments for monitoring the space environment from low earth orbit. As the program evolved, so to have the measurement capabilities such that modern DMSP spacecraft include a comprehensive suite of instruments providing estimates of precipitating electron and ion fluxes, cold/bulk plasma composition and moments, the geomagnetic field, and optical emissions in the far and extreme ultraviolet. We describe the creation of a new public database of precipitating electrons and ions from the Special Sensor J (SSJ) instrument, complete with original counts, calibrated differential fluxes adjusted for penetrating radiation, estimates of the total kinetic energy flux and characteristic energy, uncertainty estimates, and accurate ephemerides...
August 2017: Journal of Geophysical Research. Space Physics
Mike Lockwood, Mathew J Owens, Suzanne M Imber, Matthew K James, Emma J Bunce, Timothy K Yeoman
Solar cycle 24 is notable for three features that can be found in previous cycles but which have been unusually prominent: (1) sunspot activity was considerably greater in the northern/southern hemisphere during the rising/declining phase; (2) accumulation of open solar flux (OSF) during the rising phase was modest, but rapid in the early declining phase; (3) the heliospheric current sheet (HCS) tilt showed large fluctuations. We show that these features had a major influence on the progression of the cycle...
June 2017: Journal of Geophysical Research. Space Physics
S A Kiehas, N N Volkonskaya, V S Semenov, N V Erkaev, I V Kubyshkin, I V Zaitsev
We evaluate the large-scale energy budget of magnetic reconnection utilizing an analytical time-dependent impulsive reconnection model and a numerical 2-D MHD simulation. With the generalization to compressible plasma, we can investigate changes in the thermal, kinetic, and magnetic energies. We study these changes in three different regions: (a) the region defined by the outflowing plasma (outflow region, OR), (b) the region of compressed magnetic fields above/below the OR (traveling compression region, TCR), and (c) the region trailing the OR and TCR (wake)...
March 2017: Journal of Geophysical Research. Space Physics
Biagio Forte, Chris Coleman, Susan Skone, Ingemar Häggström, Cathryn Mitchell, Federico Da Dalt, Tommaso Panicciari, Joe Kinrade, Gary Bust
Ionospheric scintillation originates from the scattering of electromagnetic waves through spatial gradients in the plasma density distribution, drifting across a given propagation direction. Ionospheric scintillation represents a disruptive manifestation of adverse space weather conditions through degradation of the reliability and continuity of satellite telecommunication and navigation systems and services (e.g., European Geostationary Navigation Overlay Service, EGNOS). The purpose of the experiment presented here was to determine the contribution of auroral ionization structures to GPS scintillation...
January 2017: Journal of Geophysical Research. Space Physics
N Lugaz, C J Farrugia, R M Winslow, N Al-Haddad, E K J Kilpua, P Riley
We identify all fast-mode forward shocks, whose sheath regions resulted in a moderate (56 cases) or intense (38 cases) geomagnetic storm during 18.5 years from January 1997 to June 2015. We study their main properties, interplanetary causes and geo-effects. We find that half (49/94) such shocks are associated with interacting coronal mass ejections (CMEs), as they are either shocks propagating into a preceding CME (35 cases) or a shock propagating into the sheath region of a preceding shock (14 cases). About half (22/45) of the shocks driven by isolated transients and which have geo-effective sheaths compress pre-existing southward Bz ...
November 2016: Journal of Geophysical Research. Space Physics
V K Jordanova, W Tu, Y Chen, S K Morley, A-D Panaitescu, G D Reeves, C A Kletzing
Mechanisms for electron injection, trapping, and loss in the near-Earth space environment are investigated during the October 2012 "double-dip" storm using our ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB). Pitch angle and energy scattering are included for the first time in RAM-SCB using L and magnetic local time (MLT)-dependent event-specific chorus wave models inferred from NOAA Polar-orbiting Operational Environmental Satellites (POES) and Van Allen Probes Electric and Magnetic Field Instrument Suite and Integrated Science observations...
September 2016: Journal of Geophysical Research. Space Physics
J H Westlake, D G Mitchell, P C-Son Brandt, B G Andrews, G Clark
To achieve breakthroughs in the areas of heliospheric and magnetospheric energetic neutral atom (ENA) imaging, a new class of instruments is required. We present a high angular resolution ENA imager concept aimed at the suprathermal plasma populations with energies between 0.5 and 20 keV. This instrument is intended for understanding the spatial and temporal structure of the heliospheric boundary recently revealed by Interstellar Boundary Explorer instrumentation and the Cassini Ion and Neutral Camera. The instrument is also well suited to characterize magnetospheric ENA emissions from low-altitude ENA emissions produced by precipitation of magnetospheric ions into the terrestrial upper atmosphere, or from the magnetosheath where solar wind protons are neutralized by charge exchange, or from portions of the ring current region...
September 2016: Journal of Geophysical Research. Space Physics
Matthew K James, Emma J Bunce, Timothy K Yeoman, Suzanne M Imber, Haje Korth
We present a statistical survey of ultralow-frequency wave activity within the Hermean magnetosphere using the entire MErcury Surface, Space ENvironment, GEochemistry, and Ranging magnetometer data set. This study is focused upon wave activity with frequencies <0.5 Hz, typically below local ion gyrofrequencies, in order to determine if field line resonances similar to those observed in the terrestrial magnetosphere may be present. Wave activity is mapped to the magnetic equatorial plane of the magnetosphere and to magnetic latitude and local times on Mercury using the KT14 magnetic field model...
September 2016: Journal of Geophysical Research. Space Physics
G Clark, I Cohen, J H Westlake, G B Andrews, P Brandt, R E Gold, M A Gkioulidou, R Hacala, D Haggerty, M E Hill, G C Ho, S E Jaskulek, P Kollmann, B H Mauk, R L McNutt, D G Mitchell, K S Nelson, C Paranicas, N Paschalidis, C E Schlemm
Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV...
August 2016: Journal of Geophysical Research. Space Physics
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