Search Publications
Morphology of Ganymede's FUV auroral ovals
Saur, Joachim; Roth, Lorenz; Feldman, Paul D. +4 more
We study the morphology of Ganymede's FUV aurora by analyzing spectral images obtained over the past two decades by the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. The observations cover the eastern and western elongation as well as various magnetic latitudes of Ganymede within the Jovian plasma sheet. We find both as…
Spontaneous hot flow anomalies at Mars and Venus
Zhang, Tielong; Futaana, Yoshifumi; Persson, Moa +8 more
We report the first observations of Spontaneous Hot Flow Anomalies (SHFAs) at Venus and Mars, demonstrating their existence in the foreshocks of other planets beyond Earth. Using data from the ESA Venus Express and the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, we present magnetic and plasma observations from events at both pl…
Cold Ion Outflow Modulated by the Solar Wind Energy Input and Tilt of the Geomagnetic Dipole
Wei, Y.; Nilsson, H.; André, M. +7 more
The solar wind energy input into the Earth's magnetosphere-ionosphere system drives ionospheric outflow, which plays an important role in both the magnetospheric dynamics and evolution of the atmosphere. However, little is known about the cold ion outflow with energies lower than a few tens of eV, as the direct measurement of cold ions is difficul…
IMF dependence of energetic oxygen and hydrogen ion distributions in the near-Earth magnetosphere
Daly, P. W.; Kronberg, E. A.; Nykyri, K. +5 more
Energetic ion distributions in the near-Earth plasma sheet can provide important information for understanding the entry of ions into the magnetosphere and their transportation, acceleration, and losses in the near-Earth region. In this study, 11 years of energetic proton and oxygen observations (> 274 keV) from Cluster/Research with Adaptive P…
The transient topside layer and associated current sheet in the ionosphere of Mars
Gurnett, Donald A.; Halekas, Jasper S.; DiBraccio, Gina A. +2 more
Radar soundings from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board the Mars Express spacecraft have shown that transient layers exist in the dayside upper ionosphere of Mars. The most prominent of these features is a second layer at an altitude near 200 km, well above that of the main photoionization l…
A hybrid approach to empirical magnetosphere modeling
Tsyganenko, N. A.; Andreeva, V. A.
A new approach has been devised and explored to reconstruct magnetospheric configurations, based on spacecraft data and a synthesis of two methods of modeling the magnetic field of extraterrestrial currents. The main idea is to combine within a single framework (1) a modular structure explicitly representing separate contributions to the total fie…
MAVEN and the total electron content of the Martian ionosphere
Leblanc, François; Chaufray, Jean-Yves; Forget, François +13 more
Model studies of the ionosphere of Mars under daytime conditions reveal that for solar zenith angles of 0°-40°, the shapes and magnitudes of the electron density profiles Ne(h) change by only small amounts. This suggests that midday observations made by MAVEN instruments along slanted orbit segments can be used to represent vertical pro…
On the occurrence of magnetic reconnection equatorward of the cusps at the Earth's magnetopause during northward IMF conditions
Fuselier, S. A.; Trattner, K. J.; Petrinec, S. M. +4 more
Magnetic reconnection changes the topology of magnetic field lines. This process is most readily observable with in situ instrumentation at the Earth's magnetopause as it creates open magnetic field lines to allow energy and momentum flux to flow from the solar wind to the magnetosphere. Most models use the direction of the interplanetary magnetic…
Contribution of energetic and heavy ions to the plasma pressure: The 27 September to 3 October 2002 storm
Dandouras, I.; Daly, P. W.; Klecker, B. +5 more
Magnetospheric plasma sheet ions drift toward the Earth and populate the ring current. The ring current plasma pressure distorts the terrestrial internal magnetic field at the surface, and this disturbance strongly affects the strength of a magnetic storm. The contribution of energetic ions (>40 keV) and of heavy ions to the total plasma pressu…
Comparison of the coronal mass ejection shock acceleration of three widespread SEP events during solar cycle 24
St. Cyr, O. C.; Gopalswamy, N.; Mäkelä, P. +1 more
We studied three solar energetic particle (SEP) events observed on 14 August 2010, 3 November 2011, and 5 March 2013 by Solar Terrestrial Relations Observatory (STEREO) A, B, and near-Earth (L1) spacecraft with a longitudinal distribution of particles >90°. Using a forward modeling method combined with extreme ultraviolet and white-light images…