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Simultaneous Chandra X ray, Hubble Space Telescope ultraviolet, and Ulysses radio observations of Jupiter's aurora
MacDowall, R. J.; Waite, J. H.; Cravens, T. E. +8 more
Observations of Jupiter carried out by the Chandra Advanced CCD Imaging Spectrometer (ACIS-S) instrument over 24-26 February 2003 show that the auroral X-ray spectrum consists of line emission consistent with high-charge states of precipitating ions, and not a continuum as might be expected from bremsstrahlung. The part of the spectrum due to oxyg…
Propagation of the 12 May 1997 interplanetary coronal mass ejection in evolving solar wind structures
Arge, C. N.; Odstrcil, D.; Pizzo, V. J.
Recently, we simulated the 12 May 1997 coronal mass ejection (CME) event with a numerical three-dimensional magnetohydrodynamic model (Odstrcil et al., 2004), in which the background solar wind was determined from the Science Applications International Corporation (SAIC) coronal model (Riley et al., 2001) and the transient disturbance was determin…
Evolution and characteristics of global Pc5 ULF waves during a high solar wind speed interval
Balogh, A.; Lavraud, B.; Wild, J. A. +9 more
We present an interval of extremely long-lasting narrow-band Pc5 pulsations during the recovery phase of a large geomagnetic storm. These pulsations occurred continuously for many hours and were observed throughout the magnetosphere and in the dusk-sector ionosphere. The subject of this paper is the favorable radial alignment of the Cluster, Polar…
High-altitude cusp flow dependence on IMF orientation: A 3-year Cluster statistical study
Fedorov, A.; Budnik, E.; Grigoriev, A. +7 more
We report on the statistical properties of the plasma flows measured by the Cluster spacecraft in the high-altitude cusp region of the Northern Hemisphere as a function of the interplanetary magnetic field (IMF) orientation, with selected clock angle intervals. The technique uses a magnetic field model, taking into account the actual solar wind co…
Magnetic field variations in the Jovian magnetotail induced by solar wind dynamic pressure enhancements
Yokoyama, Takaaki; Tao, Chihiro; Kataoka, Ryuho +2 more
In order to understand the response of the Jovian magnetosphere to solar wind dynamic pressure enhancements, we investigate magnetic field variations observed by the Galileo spacecraft. The lack of solar wind monitoring just upstream of the Jovian magnetosphere is overcome by simulating a one-dimensional magnetohydrodynamic (MHD) propagation of th…
Energy deposition by Alfvén waves into the dayside auroral oval: Cluster and FAST observations
Balogh, A.; Dandouras, I.; Fazakerley, A. N. +16 more
We report in situ observations from the Cluster and FAST spacecraft showing the deposition of energy into the auroral ionosphere from broadband ULF waves in the cusp and low-latitude boundary layer. A comparison of the wave Poynting flux with particle energy and flux at both satellites indicates that energy transfer from the broadband waves to the…
Plasma sheet turbulence observed by Cluster II
Balogh, A.; Khurana, K. K.; Kistler, L. M. +8 more
Cluster fluxgate magnetometer (FGM) and ion spectrometer (CIS) data are employed to analyze magnetic field fluctuations within the plasma sheet during passages through the magnetotail region in the summers of 2001 and 2002 and, in particular, to look for characteristics of magnetohydrodynamic (MHD) turbulence. Power spectral indices determined fro…
On the sources of fast and slow solar wind
Schwadron, N. A.; Landi, E.; Feldman, U.
The slow speed solar wind as measured at the Earth orbit and beyond is characterized by its velocity of ≃400 km s-1, by its coronal composition and by its frozen-in temperature (from carbon charge-states) of 1.4-1.6 × 106 K. In contrast the fast speed solar wind is characterized by its velocity of ≃750 km s-1, its …
Characteristic magnetic field and speed properties of interplanetary coronal mass ejections and their sheath regions
Owens, M. J.; Crooker, N. U.; Siscoe, G. L. +2 more
Prediction of the solar wind conditions in near-Earth space, arising from both quasi-steady and transient structures, is essential for space weather forecasting. To achieve forecast lead times of a day or more, such predictions must be made on the basis of remote solar observations. A number of empirical prediction schemes have been proposed to fo…
Contribution of nonadiabatic ions to the cross-tail current in an O+ dominated thin current sheet
Lundin, R.; Balogh, A.; Klecker, B. +8 more
During storm times, O+ can dominate both the pressure and the density in the plasma sheet. Because of the contribution from ion outflow, the plasma sheet is already oxygen-rich prior to substorm onset. At substorm onset the fraction of O+ contributing to the pressure and density increases. In the O+ dominated thin …