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Solar particle composition: Measurements in the March 1991 event at 2.5AU
Forsyth, R.; Tappin, S. J.; Lanzerotti, L. J. +3 more
The time evolution of the very large solar particle event occurring on days 82-90 (March 23-31), 1991, as measured at 2.5 AU by the instrumentation on the Ulysses spacecraft was quite complex. Measurements by the HI-SCALE instrument of the nuclear composition (emphasizing Z≥6) of the interplanetary particles at a time resolution of two hours provi…
Energetic particle composition variations during the March 1991 events measured with the Ulysses EPAC instrument
Krupp, N.; Woch, J.; Fränz, M. +9 more
We report on energetic particle measurements obtained with the EPAC instrument on board the Ulysses spacecraft during March 1991, when a series of important flares occurred at the Sun. The EPAC instrument measures electrons (0.1-0.38 MeV), protons (0.3-1.5 MeV) and heavy ions (0.2-6.0 MeV/N). We discuss the time interval March 22 through March 29 …
Observation of non-drifting radio emissions associated with the intense solar activity in March 1991
Stone, R. G.; Fainberg, J.; Reiner, M. J.
Three very unusual radio bursts, separated in time by 4 hours and 35 minute-intervals were observed on March 28, 1991 by the radio and plasma wave (URAP) experiment on the Ulysses spacecraft. Although they are preceded by drifting type III bursts at high frequencies, they show no frequency drift at frequencies from 52 kHz down to 16 kHz. In additi…
Unusual radio and plasma wave phenomena observed in March 1991
Stone, R. G.; Fainberg, J.; Reiner, M. J.
During the intense solar flare activity in March 1991 a number of unusual radio emission and Langmuir wave phenomena were observed by the radio and plasma wave (URAP) experiment on the Ulysses spacecraft. These phenomena were associated with unusual conditions in the interplanetary medium (IPM) presumably resulting from intense solar activity. Som…
The effect of the shock of 15:43 UT March 23, 1991 on 50 keV to 5 MeV ions at Ulysses
Simnett, G. M.; Armstrong, T. P.; Roelof, E. C. +2 more
The intensities, angular distributions, and energy spectra of 50 keV to 5 MeV ions are examined in the several hour time interval when an interplanetary shock passed the Ulysses spacecraft. The increase in intensity, evolution of pitch angle distribution from upstream flow away from the shock to a post-shock “pancake” distribution, the earlier arr…
Diffusive shock acceleration and the March 1991 solar events
Krupp, N.; Keppler, E.; Korth, A. +7 more
Spectral and anisotropy measurements are reported for protons between 0.5 and 1.4 MeV during the particle increases associated with the passage of 3 interplanetary shocks past Ulysses between March 19 and March 31 1991. The data are interpreted in terms of diifusive shock acceleration in the travelling solar induced disturbances to the solar plasm…