HR: 0830h
AN: SH51A-04    [Abstracts]
TI: Magnetic Reconnection and the Deduced Properties of Plasma inside the CME/Flare Current Sheet
AU: * Lin, J
EM: jlin@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AU: Li, J
EM: jing@magnet.ifa.hawaii.edu
AF: Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 United States
AU: Forbes, T G
EM: terry.Forbes@unh.edu
AF: EOS Institute, University of New Hampshire, 39 College Road, Durham, NH 03824 United States
AU: Ko, Y
EM: kuen@uvcsiws.nascom.nasa.gov
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AU: Raymond, J C
EM: jraymond@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AU: van Ballegooijen, A A
EM: vanballe@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AB: In the present work, we display our results of studying and analyzing the observational data from UVCS and other remote sensing instruments for three CME/flare events that obviously developed a long current sheet during the eruptions. These results include the thickness of the current sheets, magnetic diffusivities and electrical conductivities (resistivities) of the plasma inside the current sheets. This is the first time that the electrical conductivity (resistivity) within magnetic reconnection region during the real eruptive processes has been deduced since the theory of magnetic reconnection was applied to the solar eruptions about 6 decades ago. The thickness of the current sheet developed during the January 8, 2002 event varies from 7 × 10⁴ km to 2.2 × 10⁵ km for altitudes between 2.5 R_⊙ and 5.5 R_⊙, with the average thickness of 1.4× 10⁵ km, and the speed of magnetic reconnection inflow near the current sheet is about 10 km s^-1. These results suggest a magnetic diffusivity of the plasma inside the current sheet to be 0.7 × 10¹² m² s^-1 (compared to the classical value for the quiet corona of 1 m² s^-1, and to the corresponding value for the "turbulent plasma" of 3.4× 10⁶ m² s^-1). For the event occurring on November 18, 2003, the data from UVCS indicate that the upper limit of the current sheet thickness at altitude of 1.7 R_⊙ is about 2.8 × 10⁴ km, and that the velocity of magnetic reconnection inflow near the current sheet ranges from 10.5 km s^-1 to 106 km s^-1. Combining these results yields a range of magnetic diffusivity from 1.4× 10¹¹ m² s^-1 to 1.4× 10¹² m² s^-1. During the event observed on March 23, 1998, the upper limit of the thickness of the current sheet in the wake of a CME is about 10⁵ km according to data from UVCS. No data for the velocity of the magnetic reconnection near the current sheet in this event were obtained. Considering the fact that this event was more gradual than the other two cases, we assume the inflow speed in this event to be 5 km s^-1. So, we obtain that the magnetic diffusivity of the plasma inside the current sheet has an upper limit of 2.5× 10¹¹ m² s^-1. We notice that values of magnetic diffusivity deduced for three different events are within the range of magnitude.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7513 Coronal mass ejections
DE: 7519 Flares
DE: 7531 Prominence eruptions
DE: 7835 Magnetic reconnection
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2005 Joint Assembly