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Titolo:
HIGH-LATITUDE ULYSSES OBSERVATIONS OF CIR ACCELERATED IONS AND ELECTRONS
Autore:
SAYLE KA; SIMNETT GM;
Indirizzi:
UNIV BIRMINGHAM,SCH PHYS & SPACE RES BIRMINGHAM B15 2TT W MIDLANDS ENGLAND UNIV BIRMINGHAM,SCH PHYS & SPACE RES BIRMINGHAM B15 2TT W MIDLANDS ENGLAND
Titolo Testata:
Astronomy and astrophysics
fascicolo: 1, volume: 331, anno: 1998,
pagine: 405 - 410
SICI:
0004-6361(1998)331:1<405:HUOOCA>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
COROTATING INTERACTION REGIONS; SOLAR-WIND; ECLIPTIC-PLANE; INTERPLANETARY ACCELERATION; PARTICLE ENHANCEMENTS; SHOCK ACCELERATION; OUTER HELIOSPHERE; AU; NUCLEONS; DYNAMICS;
Keywords:
ACCELERATION OF PARTICLES; INTERPLANETARY MEDIUM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
K.A. Sayle e G.M. Simnett, "HIGH-LATITUDE ULYSSES OBSERVATIONS OF CIR ACCELERATED IONS AND ELECTRONS", Astronomy and astrophysics, 331(1), 1998, pp. 405-410

Abstract

From the comparison of the intensity maxima of similar to 1 MeV/nuc. ions with those of the 40-65 keV electrons and higher energy ions (similar to 2-4 and 4-8 MeV/nuc.), during Ulysses' ascent to the solar south pole, 1992-1994, evidence has been found for the similar to 1 MeV/nuc. ions observed at high latitude by the Ulysses spacecraft to have originated at mid-latitudes and greater radial distances. The key observations presented in this paper are; i) The similar to 1 MeV/nuc.) ionintensity maxima were observed to decay exponentially with latitude, above the streamer belt, whereas the electron intensity maxima and higher energy (similar to 4-8 MeV/nuc.) ion intensity maxima varied abouta constant level, ii) When the ratios were taken of the ion intensitymaxima to the electron intensity maxima for each of the CIR events, above the streamer belt, the ratios decayed exponentially with latitude, and iii) Upon the spacecraft's departure from the streamer belt, theelectron maxima were observed to be delayed by similar to 1-4 days, with respect to the similar to 1 MeV/nuc. ion maxima. Within the streamer belt they had been typically simultaneous. Evidence was also found for a delay in the higher energy (greater than or similar to 2 MeV/nuc.) ions with respect to the lower energy similar to 1 MeV/nuc. ions. From the exponential decay of the ion/electron ratios above the streamer belt, we concluded that the similar to 1 MeV/nuc. ions originated from the CIR reverse shock at lower latitudes and greater radial distances, along with the electrons. The observed delays in the electrons andhigher energy ions were a consequence of the particles travelling from the distant reverse shack. Hence, it appears that the ions were accelerated at the reverse shock at lower latitudes, and not at the local poleward propagating reverse shocks as had been previously suggested.

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Documento generato il 04/12/20 alle ore 22:30:39