Search Publications
Impact factor for the ionospheric total electron content response to solar flare irradiation
Zhang, W.; Cai, L.; Zhang, D. H. +4 more
On the basis of ionospheric total electron content (TEC) enhancement over the subsolar region during flares, and combined with data of the peak X-ray flux in the 0.1-0.8 nm region, EUV increase in the 0.1-50 and 26-34 nm regions observed by the SOHO Solar EUV Monitor EUV detector, also with the flare location on the solar disc, the relationship am…
Magnetic effects of the substorm current wedge in a “spread-out wire” model and their comparison with ground, geosynchronous, and tail lobe data
Sergeev, V. A.; Baumjohann, W.; Tsyganenko, N. A. +3 more
Although the substorm current wedge (SCW) is recognized as a basic 3-D current system of the substorm expansion phase, its existing models still do not extend beyond a cartoon-like sketch, and very little is known of how well they reproduce magnetic variations observed in the magnetosphere during substorms. A lack of a realistic quantitative SCW m…
Small-scale structures in Saturn's ultraviolet aurora
Bonfond, B.; Gérard, J. -C.; Grodent, D. +3 more
On 26 August 2008, the Ultraviolet Imaging Spectrograph Subsystem (UVIS) instrument onboard the Cassini spacecraft recorded a series of spatially resolved spectra of the northern auroral region of Saturn. Near periapsis, the spacecraft was only five Saturn radii (RS) from the surface and spatially resolved auroral structures as small as…
Evolution of an MHD-scale Kelvin-Helmholtz vortex accompanied by magnetic reconnection: Two-dimensional particle simulations
Hasegawa, H.; Fujimoto, M.; Shinohara, I. +1 more
We have performed 2.5-dimensional full particle simulations of an MHD-scale Kelvin-Helmholtz (KH) vortex and accompanying magnetic reconnection. This is the first study of so-called vortex-induced reconnection (VIR) using kinetic simulations. First, as a key property of the VIR, we found that magnetic reconnection occurs at multiple points in the …
Simulation of electromagnetic ion cyclotron triggered emissions in the Earth's inner magnetosphere
Omura, Yoshiharu; Shoji, Masafumi
In a recent observation by the Cluster spacecraft, emissions triggered by electromagnetic ion cyclotron (EMIC) waves were discovered in the inner magnetosphere. We perform hybrid simulations to reproduce the EMIC triggered emissions. We develop a self-consistent one-dimensional hybrid code with a cylindrical geometry of the background magnetic fie…
Revisiting two-step Forbush decreases
Spence, H. E.; Blake, J. B.; Jordan, A. P. +1 more
Interplanetary coronal mass ejections (ICMEs) and their shocks can sweep out galactic cosmic rays (GCRs), thus creating Forbush decreases (FDs). The traditional model of FDs predicts that an ICME and its shock decrease the GCR intensity in a two-step profile. This model, however, has been the focus of little testing. Thus, our goal is to discover …
Magnetosphere-ionosphere coupling in Jupiter's middle magnetosphere: Computations including a self-consistent current sheet magnetic field model
Nichols, J. D.
In this paper we consider the effect of a self-consistently computed magnetodisc field structure on the magnetosphere-ionosphere coupling current system at Jupiter. We find that the azimuthal current intensity, and thus the stretching of the magnetic field lines, is dependent on the magnetosphere-ionosphere coupling current system parameters, i.e.…
Response of Saturn's auroral ionosphere to electron precipitation: Electron density, electron temperature, and electrical conductivity
Galand, Marina; Moore, Luke; Miller, Steve +2 more
In the high-latitude regions of Saturn, the ionosphere is strongly coupled to the magnetosphere through the exchange of energy. The influx of energetic particles from Saturn's magnetosphere enhances the ionospheric densities and temperatures, affects the electrodynamical properties of the ionosphere, and contributes to the heating of the thermosph…
Comparison of a statistical model for magnetic islands in large current layers with Hall MHD simulations and Cluster FTE observations
Hwang, K. -J.; Drake, J. F.; Swisdak, M. +1 more
Magnetic islands have been observed in long current layers for various space plasmas, including the magnetopause and solar corona. In previous work exploring these magnetic islands, a statistical model was developed that described their formation, growth, convection, and coalescence in very large systems, for which simulations prove inadequate. An…
Polar coronal holes during the past solar cycle: Ulysses observations
Zurbuchen, Thomas H.; von Steiger, Rudolf
During its nearly 19-year mission, Ulysses pioneered novel measurements of the three-dimensional heliosphere and particularly in situ observations of high-latitude solar wind from polar coronal holes (PCHs). Winds from PCHs exhibit constant elemental abundances to within the limits of the measurements, indicative of the fact that such winds truly …