On the E-W asymmetry and the generation of ESP events

• Published in: Solar physics Vol. 93; no. 1; pp. 195 - 210
• Main Authors: SARRIS, E. T, ANAGNOSTOPOULOS, G. C, TROCHOUTSOS, P. C
• Format: Journal Article
• Language: English
• Published: Boston, MA Reidel 01.06.1984; Dordrecht
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Flares, bursts, and related phenomena; Solar physics; Solar system; Interplanetary magnetic field; Energetics; Ions; Satellite observation; Solar event; Shock wave; Solar flare
• ISSN: 0038-0938; 1573-093X
• DOI: 10.1007/BF00156665

Observations of energetic-ion-intensity enhancements (E greater than or equal to 290 keV) associated with solar-flare-generated shock waves (solar-flare ESP events), obtained during nearly a decade by the APL/JHU instruments on board the earth orbiters IMP-7 and 8, are used to examine the role of the heliolongitude-dependent large-scale shock morphology in relation to the upstream interplanetary magnetic field in the formation of these ESP events. It is shown that a clear east-west solar-hemisphere asymmetry is present in the distribution of the ESP relative-intensity enhancements with respect to the heliolongitudes of the shock-wave source-flare sites. The large ion-intensity enhancements superimposed on the ambient solar-flare ion population are preferentially associated with solar-flare sites locoated to the east of the spacecraft meridian, whereas on the average only weak ESP events are associated with solar-flare sites to the west of the spacecraft meridian. The observed asymmetry and its implications for the dominant processes in the generation of the solar-flare ESP events are discussed on the basis of this extensive survey.