Search Publications
Modified solar flux index for upper atmospheric applications
Maruyama, Takashi
The F10.7 solar flux index was modified in order to better describe short-term variations in solar extreme ultraviolet (EUV) irradiance for application in ionosphere and thermosphere studies. Several parameters were computed from the F10.7 time series with the assistance of an artificial neural network (ANN) technique, and th…
Influence of heavy ionospheric ions on substorm onset
Winglee, R. M.; Harnett, E.
Multifluid/multiscale simulations are used to examine the influence of ionospheric outflows on two substorms that occurred on August 13, 2001. Both substorms had well defined onsets in Cluster ion spectrometer (CIS) data of ion composition of the plasma sheet. It is shown that the model is able to account for two orders of magnitude variation in t…
Periodicity analysis of Jovian quasi-periodic radio bursts based on Lomb-Scargle periodograms
Morioka, Akira; Tsuchiya, Fuminori; Misawa, Hiroaki +3 more
The Jovian polar magnetosphere has relativistic particle accelerations with quasi-periodicity (hereafter QP accelerations) that are accompanied by periodic auroral emissions and low-frequency radio bursts called quasi-periodic (QP) bursts. Some previous observations suggested a possible physical relationship between the QP accelerations and QP rad…
Cassini Plasma Spectrometer and hybrid model study on Titan's interaction: Effect of oxygen ions
Kallio, E.; Janhunen, P.; Crary, F. +7 more
During the Cassini Titan flyby on 2 July 2006 (T15), Titan was surrounded by a magnetospheric plasma flow with density about 0.1 cm-3 as measured by Cassini Plasma Spectrometer (CAPS). A very low fraction of water group ions (O+) was detected in the flow dominated by hydrogen ions. We show that Titan's plasma interaction can …
Multipoint observations of coronal mass ejection and solar energetic particle events on Mars and Earth during November 2001
Vennerstrom, S.; Falkenberg, T. V.; Brain, D. A. +2 more
Multipoint spacecraft observations provide unique opportunities to constrain the propagation and evolution of interplanetary coronal mass ejections (ICMEs) throughout the heliosphere. Using Mars Global Surveyor (MGS) data to study both ICME and solar energetic particle (SEP) events at Mars and OMNI and Geostationary Operational Environmental Satel…
Mesoscale PIC simulation of double layers and electron holes affecting parallel and transverse accelerations of electrons and ions
Singh, Nagendra; Araveti, Sudeepth; Wells, Earl B.
We study the dynamical behavior of potential structures in the auroral upward current region. The study is based on a large two-dimensional particle-in-cell simulation. A double layer (DL) forms in the auroral potential structure in the counterstreaming expansion of cold and hot plasmas from bottom (ionospheric side) and top (magnetospheric side),…
Reconstruction of steady, three-dimensional, magnetohydrostatic field and plasma structures in space: Theory and benchmarking
Hasegawa, Hiroshi; Sonnerup, Bengt U. Ö.
A first attempt is made to reconstruct magnetic field and pressure distributions in steady, three-dimensional (3D), magnetohydrostatic structures, using field and plasma data taken by two proximate spacecraft as they traverse such structures in space. The reconstruction is based on integration of the four scalar magnetohydrostatic equations for th…
Compressible Kelvin-Helmholtz instability in supermagnetosonic regimes
Le Contel, O.; Califano, F.; Pegoraro, F. +2 more
We investigate the transition from submagnetosonic to supermagnetosonic regimes in the presence of a sheared flow and density variations typically observed between the solar wind and the Earth's magnetosphere. In particular, we show the possibility of generating quasi-perpendicular magnetosonic shock structures under typical conditions that can be…
The importance of thermal electron heating in Titan's ionosphere: Comparison with Cassini T34 flyby
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +9 more
We use a new magnetohydrodynamic (MHD) model to study the effects of thermal-electron heating in Titan's ionosphere. This model improves the previously used multispecies MHD model by solving both the electron and ion pressure equations instead of a single plasma pressure equation. This improvement enables a more accurate evaluation of ion and elec…
Cluster observations of bow shock energetic ion transport through the magnetosheath into the cusp
Fuselier, S. A.; Kronberg, E.; Nykyri, K. +2 more
The observation of energetic particles by polar orbiting satellites in the magnetospheric cusp resulted in a controversy about their source region. It has been suggested that these cusp energetic particles (CEP) with significant fluxes from magnetosheath energies up to several hundred keV/e are accelerated locally in the cusp by the turbulence fou…