Probing the magnetic topologies of magnetic clouds by means of solar energetic particles. (Reannouncement with new availability information)

Technical Report · Sat Jun 01 04:00:00 EDT 1991

OSTI ID:177486

Kahler, S W; Reames, D V

Magnetic clouds are large (<0.25 AU) interplanetary regions with topologies consistent with those of magnetic loops. They are of interest because they may be an interplanetary signature of coronal mass ejections. Clouds have been identified in solar wind data by their magnetic properties and by the presence of bidirectional particle fluxes. Two possible closed magnetic topologies have been considered for clouds: (1) an elongated bottle with field lines rooted at both ends in the Sun and (2) a detached magnetic bubble or plasmoid consisting of closed field lines. The inferred topologies are also consistent with open field lines that converge beyond 1 AU. We have used solar energetic particles (SEPs) as probes of the cloud topologies. The rapid access of SEPs to the interiors of many clouds indicates that the cloud field lines extend back to the Sun and hence are not plasmoids. The small modulation of galactic cosmic rays associated with clouds also suggests that the magnetic fields of clouds are not closed.

• Research Organization: Boston Coll., Chestnut Hill, MA (United States). Inst. for Space Research
• OSTI ID: 177486
• Report Number(s): AD-A--256838/4/XAB; CNN: Contract F19628-90-K-0006
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FLUX
PLASMOIDS
TOPOLOGY