Ulysses ESA Guest Investigator


This is one of the five accepted Ulysses ESA Guest Investigator proposals which involves collaboration with the magnetometer team.

The structure and dynamics of interplanetary coronal mass ejections and microstreams observed by Ulysses

Dr. Peter Cargill

Imperial College of Science, Technology and Medicine, University of London

Abstract

A theoretical and computational investigation of the structure of interplanetary coronal mass ejections (CMEs) and microstreams is proposed. The properties of CMEs at both large heliocentric distances and mid latitude will be contrasted with those expected at the Earth's orbit. Particular emphasis will be placed on how CMEs in low and high speed wind regions differ, and on how portions of the same CME that are in regions of different wind speed evolve relative to each other. The results for mid-latitude will be compared with Ulysses observations obtained between early 1993 and 1994, and as the spacecraft heads to Jupiter and back. It is expected that this work will shed fundamental light on the magnetohydrodynamic processes that govern the motion of CMEs in the solar wind. It is also anticipated that they will contribute to our understanding of the multi-dimensional topology of CMEs, since observations from multiple spacecraft (e.g. Ulysses, Wind and ACE) can be expected to provide data from different locations.

The possible solar origin of microstreams will also be examined. Working from the hypothesis that they are the interplanetary remains of small-scale plasma jets, or magnetic elements, as seen by HRTS and SOHO, the motion of these elements over several AU will be modelled, and the results contrasted with the Ulysses observations. If these structures are to survive from the Sun to the orbit of Ulysses, they must be underdoing a minimal amount of dissipation as they move through the wind. We will assess this possibility in light of current knowledge of dissipative processes. Finally, this study offers an opportunity to compare how large (CMEs) and small (microstreams) solar phenomena behave as they move through the solar wind.

Address


The Blackett Laboratory
Imperial College
Prince Consort Road
London SW7 2BZ
United Kingdon

Email: p.cargill@ic.ac.uk

Tel: +44 171 594 7773

Fax: +44 171 594 7772

WWW: http://www.sp.ph.ic.ac.uk


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Last changed 29th May 1997 by Tim Horbury.