Evolution of Inner Plasma Sheet Pressure Associated with Substorm Onset

Details Evolution of Inner Plasma Sheet Pressure Associated with Substorm Onset Evolution of Inner Plasma Sheet Pressure Associated with Substorm Onset

Dec 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufmsm43a1703x&link_type=abstract

American Geophysical Union, Fall Meeting 2008, abstract #SM43A-1703

Other

2721 Field-Aligned Currents And Current Systems (2409), 2730 Magnetosphere: Inner, 2744 Magnetotail, 2760 Plasma Convection (2463), 2764 Plasma Sheet

Scientific paper

We have investigated the evolution of plasma pressure associated with substorms onsets within the inner equatorial plasma sheet using the five THEMIS spacecraft data during the 2008 tail season. The central plasma sheet thermal pressure is estimated from the measured off-equatorial plane thermal pressure and magnetic pressure. Based on simple pressure balance, we expect the reduction of cross-tail current associated with current wedge formation to be associated with a reduction of the plasma sheet pressure that initiates at a radial distance of ~-10RE and expands tailward. However, our results show that associated with substorm, the plasma pressure undergoes a large enhancement after onset earthward of ~-11RE. Also, associated with the onset, a gradual precursor pressure increase is found several minutes before the large enhancement, and the precursor appears to be associated with the gradual enhancement of the substorm breakup arc that has been observed a few minutes prior to the dramatic brightening and breakup of that arc. One the other hand, the plasma pressure beyond ~-16RE shows a remarkable decrease after onset. During the recovery phase, the pressure gradually returns to its original level. These results indicate that during the substorm expansion phase, the current wedge connects to the region further tailward than ~-16RE. The pressure increase earthward of ~-11RE could be related to the substorm current system oppositely directed to the substorm current wedge, which has recently been observed equatorward of the substorm onset region in the ionosphere. The relationship between the auroral break up arc, which is believed to map to ~-10RE, and the pressure and current evolution in that region of the plasma sheet near the time of onset becomes an interesting question for future study.

Affiliated with

Also associated with

No associations

Rating

Evolution of Inner Plasma Sheet Pressure Associated with Substorm Onset does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Evolution of Inner Plasma Sheet Pressure Associated with Substorm Onset, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evolution of Inner Plasma Sheet Pressure Associated with Substorm Onset will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1097462