Search Publications
The Association of Cusp-Aligned Arcs With Plasma in the Magnetotail Implies a Closed Magnetosphere
Dandouras, I.; Anderson, B. J.; Fazakerley, A. N. +7 more
We investigate a 15-day period in October 2011. Auroral observations by the Special Sensor Ultraviolet Spectrographic Imager instrument onboard the Defense Meteorological Satellite Program F16, F17, and F18 spacecraft indicate that the polar regions were covered by weak cusp-aligned arc (CAA) emissions whenever the interplanetary magnetic field (I…
Indirect Observations of Electric Fields at Comet 67P
Gunell, H.; Nilsson, H.; Goetz, C. +2 more
No spacecraft visiting a comet has been equipped with instruments to directly measure the static electric field. However, the electric field can occasionally be estimated indirectly by observing its effects on the ion velocity distribution. We present such observations made by the Rosetta spacecraft on 19 April 2016, 35 km from the nucleus. At thi…
Local Electron Density Depletions in the Martian Upper Ionosphere Obtained From MARSIS: Comparison With ASPERA-3, and MAVEN, and the Connection With Crustal Magnetic Fields
Frahm, R. A.; Duru, F.; Hughes, D. +3 more
Steep electron density depletions in the Martian ionosphere are important, especially because they could be regions of significant plasma escape. Local electron density profiles of the Martian ionosphere obtained from the radar sounder onboard the Mars Express spacecraft often show large fluctuations. In some cases, these fluctuations are observed…
On Current Sheets and Associated Density Spikes in Titan's Ionosphere as Seen From Cassini
Edberg, Niklas J. T.; Vigren, Erik; Bertucci, Cesar +3 more
The Cassini spacecraft made in-situ measurements of Titan's plasma environment during 126 close encounters between 2004 and 2017. Here we report on observations from the Radio and Plasma Waves System/Langmuir probe instrument (RPWS/LP) from which we have observed, primarily on the outbound leg, a localized increase of the electron density by up to…
Space Weather Disturbances in Non-Stormy Times: Occurrence of dB/dt Spikes During Three Solar Cycles
Gunell, H.; Hamrin, M.; Opgenoorth, H. +8 more
Spatio-temporal variations of ionospheric currents cause rapid magnetic field variations at ground level and Geomagnetically Induced Currents (GICs) that can be harmful for human infrastructure. The risk for large excursions in the magnetic field time derivative, "dB/dt spikes", is known to be high during geomagnetic storms and substorms. However,…
Geocoronal Solar Wind Charge Exchange Process Associated With the 2006-December-13 Coronal Mass Ejection Event
Toriumi, Shin; Mitsuda, Kazuhisa; Yamasaki, Noriko Y. +1 more
We report the discovery of a geocoronal solar wind charge exchange (SWCX) event corresponding to the well-known 2006 December 13th coronal mass ejection (CME) event. Strong evidence for the charge exchange origin of this transient diffuse emission is provided by prominent non-thermal emission lines at energies of O7+, Ne9+, M…
Global-MHD Simulations Using MagPIE: Impact of Flux Transfer Events on the Ionosphere
Strugarek, Antoine; Vaidya, Bhargav; Paul, Arghyadeep
This study presents a recently developed two-way coupled magnetosphere-ionosphere model named "MagPIE" that enables the investigation of the impact of flux transfer events (FTEs) on the ionosphere. Our findings highlight the prominent role of cusp-FTE reconnection in influencing the ionosphere. The typical morphology of an FTE signal, represented …
The Effects of the Polar Rain on the Polar Wind Ion Outflow From the Nightside Ionosphere
Rong, Zhaojin; Wang, Jing; Yang, Qian +7 more
The polar wind, consisting of low-energy ions and electrons, is an outflow along the open magnetic field lines from the polar cap ionosphere to the magnetosphere. Previous studies found that both solar radiation and solar wind electromagnetic energy are the two main energy sources for the polar wind. The polar rain, being field-aligned precipitati…
Energization of Cold Protons and Helium Ions by EMIC Waves in the Inner Magnetosphere: Hybrid Simulations
Lee, Ensang; Min, Kyungguk; Kwon, Jong-Woo +3 more
Electromagnetic ion cyclotron (EMIC) waves generated by hot anisotropic (T⊥ > T∥) protons (∼10-100 keV), play an important role in accelerating cold (<1 eV) protons (H+) and helium (He+) ions in the magnetosphere. Using a hybrid code with parameters found in the inner magnetosphere, we examine when…
Multipoint Cluster Observations of Kinetic Alfvén Waves, Electron Energization, and O+ Ion Outflow Response in the Mid-Altitude Cusp Associated With Solar Wind Pressure and/or IMF BZ Variations
Chaston, Christopher C.; Hull, Arthur J.; Damiano, Peter A.
We report the properties of low frequency (LF) electromagnetic fluctuations (≤11 Hz) in relation to input electron and ion outflow response observed by Cluster in the mid-altitude cusp during high solar wind dynamic pressure PSW and active magnetospheric conditions (Kp = 4+). The multipoint observations reveal the dynamic int…