Search Publications
Supercriticality of ICME and CIR shocks
Zhou, Xiaoyan; Smith, Edward J.
Interplanetary coronal mass ejection (ICME) and corotating interaction region (CIR) shocks are characterized in terms of supercriticality introduced by Edmiston and Kennel (1984) to classify shocks based on whether dissipation is provided by electron resistivity alone or also requires ion viscosity. The condition for determining supercriticality i…
The use of the Poynting vector in interpreting ULF waves in magnetospheric waveguides
Wright, A. N.; Elsden, T.
We numerically model ultralow frequency (ULF) waves in the magnetosphere assuming an ideal, low-β, inhomogeneous plasma waveguide. The waveguide is based on the hydromagnetic box model. We develop a novel boundary condition that drives the magnetospheric boundary by pressure perturbations, in order to simulate solar wind dynamic pressure fluctuati…
Improved outer boundary conditions for outer radiation belt data assimilation using THEMIS-SST data and the Salammbo-EnKF code
Daglis, I. A.; Maget, V.; Sicard-Piet, A. +4 more
Over the last decade, efforts have been made in the radiation belt community to develop data assimilation tools in order to improve the accuracy of radiation belts models. In this paper we present a new method to correctly take into account the outer boundary conditions at L* = 8 in such an enhanced model of the radiation belts. To do that we base…
Discovery of suprathermal Fe+ in Saturn's magnetosphere
Krimigis, S. M.; Mitchell, D. G.; Hamilton, D. C. +3 more
Measurements in Saturn's equatorial magnetosphere from mid-2004 through 2013 made by Cassini's charge-energy-mass ion spectrometer indicate the presence of a rare, suprathermal (83-167 keV/e) ion species at Saturn with mass ~56 amu that is likely Fe+. The abundance of Fe+ is only ~10-4 relative to that of W+
Current-driven Langmuir oscillations and amplitude modulations—Another view on electron beam-plasma interaction
Sauer, K.; Sydora, R. D.
origin of Langmuir amplitude modulations and harmonic waves observed in the solar wind and in planetary foreshock regions is investigated in beam plasmas where the saturation process of the beam instability is accompanied with the formation of a plateau distribution. This saturated state represents a current which is shown to drive homogeneous ele…
A statistical study of the low-altitude ionospheric magnetic fields over the north pole of Venus
Luhmann, J. G.; Russell, C. T.; Zhang, T. L. +3 more
Examination of Venus Express (VEX) low-altitude ionospheric magnetic field measurements during solar minimum has revealed the presence of strong magnetic fields at low altitudes over the north pole of Venus. A total of 77 events with strong magnetic fields as VEX crossed the northern polar region were identified between July 2008 and October 2009.…
The Earth's bow shock velocity distribution function
Maksimovic, M.; Meziane, K.; Hamza, A. M. +1 more
It is well established that interplanetary disturbances cause the Earth's bow shock to move sunward or earthward. Since the launch of the Cluster mission, precise determination of the shock velocity was carried out allowing for the possibility to perform sophisticated investigations about the shock dynamics. The shock normal and velocity are deter…
Multiscale field-aligned current analyzer
Marghitu, O.; Narita, Y.; Vogt, J. +3 more
The magnetosphere-ionosphere coupling is achieved, essentially, by a superposition of quasi-stationary and time-dependent field-aligned currents (FACs), over a broad range of spatial and temporal scales. The planarity of the FAC structures observed by satellite data and the orientation of the planar FAC sheets can be investigated by the well-estab…
Parallel-dominant and perpendicular-dominant components of the fast bulk flow: Comparing with the PSBL beams
Dunlop, M. W.; Baumjohann, W.; Rème, H. +3 more
Utilizing multipoint observations by the Cluster satellites, we investigated the ion distributions of the fast bulk flows (FBFs) in the plasma sheet. Simultaneous observation by C1 and C3 revealed that parallel-dominant and perpendicular-dominant components of the flows coexist and correspond to Bx-dominant and Bz-dominant ma…
Ion composition in Titan's exosphere via the Cassini Plasma Spectrometer I: T40 encounter
Johnson, R. E.; Smith, H. T.; Crary, F. J. +1 more
investigate the complex interaction between Saturn's magnetosphere and Titan's upper ionosphere using ion data acquired by the Cassini Plasma Spectrometer (CAPS) during the T40 encounter. Bounds on ion-group abundances at altitudes between ~2733 and ~12,541 km are determined by fitting mass spectra with model functions derived from instrument cali…