Low Frequency Waves During the March 1991 Solar Particle Events at the Ulysses Spacecraft
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STONE, E.C., (Jet Propulsion Laboratory CaliforniaInstitute of Technology). The Anomalous Cosmic RayComponent
The anomalous cosmic rays are believed to be a sample of theneutral local interstellar medium that flows into the heliosphere,becomes singly ionized and is immediately picked up by the outwardflowing solar wind. On reaching the termination shock in theouter heliosphere, the ions are accelerated to cosmic ray energiesand subsequently drift and diffuse back into the innerheliosphere. Studies of the anomalous cosmic rays by the Pioneer10 and 11 and Voyager 1 and 2 spacecraft in the outer heliospherehave revealed the inward drift of these energetic ions along theheliosphereic neutral sheet and have provided new information onthe elemental and isotopic composition of the local interstellarmedium.
STONE, E.C., (Jet Propulsion Laboratory CaliforniaInstitute of Technology). The Future of Voyager 1 and 2
Following the Voyager 2 encounter with Neptune in August, 1989,the two Voyager spacecraft embarked on the Voyager InterstellarMission. Heading in the general direction of the impinginginterstellar wind, the two spacecraft regularly return data on theparticles, magnetic fields, and electromagnetic waves in the outerheliosphere and observe extreme ultraviolet radiation fromgalactic and extragalactic sources. In September, 1992, Voyager 1and 2 will be at distances of 50 AU and 38 AU and latitudes of 32and 8. Both spacecraft have enough power and fuel to continueoperating until at least 2015, when they will be 130 and lii AUfrom the Sun, possibly beyond the heliopause and in theinterstellar medium.
TSURUT~I, B.T. and SMITH E.J., (MS 169506, JetPropulsion Laboratory, Pasadena, CA 91109, USA),SOUTHWOOD, D.J. and BALOGH, A., (Blackett Lab., ImperialCollege, London SW7 2BZ, UK). Low Frequency WavesDuring the March 1991 Solar Particle Events at theUlysses Spacecraft
Using the Ulysses spacecraft mangetometer data we review thevarious types of low frequency waves and other disturbancesdetected during the major March 23-25, 1991 interplanetaryparticle and solar wind events. Both transverse and highlycompressional signals are detected. The latter are unusual forthe solar wind and we present evidence of the occurrence of bothlocalised megnetosonic waves and drift mirror disturbances. Boththese types of wave have been detected in circumstances wherebeams (of shock reflected or pick up ions) are present in theplasma or the plasma anisotropy was very large. We discuss thepotential role of the waves detected in waveparticle interactionprocesses during the solar events.