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Evolution of large-scale plasma structures in comets: kinematics and physics
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Brandt, John C. |
| Copyright Year | 1993 |
| Description | Cometary and solar wind data from December 1985 through April 1986 are presented for the purpose of determining the solar wind conditions associated with comet plasma tail disconnection events (DE's). The cometary data are from The International Halley Watch Atlas of Large-Scale Phenomena (Brandt, Niedner, and Rahe, 1992). In addition, we present the kinematic analysis of 4 DE's, those of Dec. 13.5 and 31.2, 1985, and Feb. 21.7 and 28.7, 1986. The circumstances of these DE's clearly illustrate the need to analyze DE's in groups. In situ solar wind measurements from IMP-8, ICE, and PVO were used to construct the variation of solar wind speed, density, and dynamic pressure during this interval. Data from these same spacecraft plus Vega-1 were used to determine the time of 48 current sheet crossings. These data were fitted to heliospheric current sheet curves extrapolated from the corona into the heliosphere in order to determine the best-fit source surface radius for each Carrington rotation. Comparison of the solar wind conditions and 16 DE's in Halley's comet (the four DE's discussed in this paper and 12 DE's in the literature) leaves little doubt that DE's are associated primarily with crossings of the heliospheric current sheet and apparently not with any other property of the solar wind. If we assume that there is a single or primary physical mechanism and that Halley's DE's are representative, efforts at simulation should concentrate on conditions at current sheet crossings. The mechanisms consistent with this result are sunward magnetic reconnection and tailward magnetic reconnection, if tailward reconnection can be triggered by the sector boundary crossing. |
| File Size | 1343634 |
| Page Count | 42 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19940018778 |
| Archival Resource Key | ark:/13960/t1zd2v494 |
| Language | English |
| Publisher Date | 1993-10-01 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics Heliosphere Solar Rotation Magnetohydrodynamics Current Sheets Density Number/volume Magnetic Field Reconnection Comet Tails Wind Velocity Halley's Comet Solar Wind Space Plasmas Dynamic Pressure Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
