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Low-energy solar electrons and ions observed at Ulysses February-April, 1991: The inner heliosphere as a particle reservoir
Simnett, G. M.; Tappin, S. J.; Lanzerotti, L. J. +3 more
Ulysses observations at 2.5 AU of 38-315 keV electrons and 61-4752 keV ions during February-April 1991 suggest in several ways that, during periods of sustained high solar activity, the inner heliosphere serves as a “reservoir” for low-energy solar particles. Particle increases were not associated one-to-one with large X-ray flares because of thei…
Nonlinear magnetosonic waves and mirror mode structures in the March 1991 Ulysses interplanetary event
Tsurutani, Bruce T.; Smith, Edward J.; Balogh, Andre +1 more
In examining the March 23-25, 1991 Ulysses (2.2 AU) high speed solar wind events, we find two distinct plasma wave modes: steepened magnetosonic waves with whistler precursors and mirror mode structures. These two modes are locally generated by plasma instabilities, presumably associated with anisotropies existing in the energetic shock particles …
Ultraviolet imaging of the Jovian aurora with the Hubble Space Telescope
Paresce, F.; Vidal-Madjar, A.; Dols, V. +2 more
We present here for the first time a Lyman-α image of the north polar region of Jupiter obtained with the Faint Object Camera (FOC) on board the Hubble Space Telescope a few hours after the encounter of the ULYSSES spacecraft with Jupiter. The presence of high latitude regions of enhanced emission is clearly observed. A comparison with the locatio…
Solar wind Halo electrons from 1-4 AU
McComas, D. J.; Bame, S. J.; Phillips, J. L. +2 more
In this study we use observations from the Ulysses solar wind electron spectrometer to make a first examination of the evolution of the solar wind suprathermal or halo electron population as a function of heliocentric distance beyond 1 AU. Solar wind electron analyzers previously flown to distances >1 AU did not resolve the halo electron distri…
Evidence for Langmuir wave collapse in the interplanetary plasma
Goetz, K.; Kellogg, Paul J.; Monson, S. J. +1 more
With the Fast Envelope Sampler part of the URAP experiment on Ulysses, we have observed much rapidly varying structure in plasma waves in the solar wind. Here we discuss extremely narrow (1 ms) structures observed together with electrostatic Langmuir waves, as well as some broader Langmuir wave packets
Ulysses: Interplanetary shocks between 1 and 4 AU
Balogh, A.; Forsyth, R. J.; Burton, M. E. +3 more
The complex solar events of March 1991 are evident as a large increase in the rate of occurrence of interplanetary shocks. Using Ulysses magnetic field and plasma measurements, 32 forward shocks and 7 reverse shocks have been identified in the 280 day interval from October 26, 1990 to August 1, 1991. The March events alone have produced 9 shocks, …
Low frequency magnetic signals associated with Langmuir waves
Balogh, A.; Goetz, K.; Forsyth, R. J. +4 more
With the URAP experiment on Ulysses, we have observed low frequency signals with a magnetic component in close time correlation with electrostatic Langmuir waves at the plasma frequency. In most, if not all, of these cases, the Langmuir waves are part of a Type III solar burst. We investigate this effect and show that the low frequency waves are i…
Ulysses plasma observations of coronal mass ejections near 2.5 AU
Balogh, A.; McComas, D. J.; Forsyth, R. J. +5 more
The Ulysses solar wind plasma experiment observed a series of interplanetary shocks and coronal mass ejections (CMEs), the latter evidenced by counterstreaming electrons and a variety of ion signatures, during March and April 1991. A striking sequence was observed near 2.5 AU from March 23 through April 2, with the second of two counterstreaming e…
Galileo and Ulysses dust measurements: Fz Venus to Jupiter
Grün, E.; Kissel, J.; Mann, I. +13 more
The Galileo and Ulysses spaceprobes carry two similar dust detectors through interplanetary space from Venus to Jupiter. We report here on impacts which correspond to dust particles above a mass threshold of about 10-13g for which we have complete records. Between December 1989 and January 1992 Galileo repeatedly traversed interplanetar…
Ulysses observations of escaping VLF emissions from Jupiter
MacDowall, R. J.; Kaiser, M. L.; Desch, M. D. +5 more
The Ulysses URAP experiment has detected Jovian radio emissions in the VLF range at distances from Jupiter in excess of 1.5 A.U. The URAP observations represent the first synoptic observations of Jupiter in the VLF band, 3 to 30 kHz. In this band lie the low-frequency extent of the bKOM emission, the escaping continuum emission, and the Jovian typ…