A simulation study of particle energization observed by THEMIS spacecraft during a substorm

Physics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

4

Magnetospheric Physics: Magnetotail, Magnetospheric Physics: Substorms, Magnetospheric Physics: Numerical Modeling, Magnetospheric Physics: Solar Wind/Magnetosphere Interactions

Scientific paper

Energetic ions with hundreds of keV energy are frequently observed in the near-Earth tail during magnetospheric substorms. We examined the sources and acceleration of ions during a magnetospheric substorm on 1 March 2008 by using Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Cluster observations and numerical simulations. Four of the THEMIS spacecraft were aligned at y GSM = 6 R E during a very large substorm (AE = 1200) while the Cluster spacecraft were located about 5 R E above the auroral ionosphere. For 2 h before the substorm, Cluster observed ionospheric oxygen flowing out into the magnetosphere. After substorm onset the THEMIS P3 and P4 spacecraft located in the near-Earth tail (x GSM = -9 R E and -8 R E , respectively) observed large fluxes of energetic ions up to 500 keV. We used calculations of millions of ions of solar wind and ionospheric origin in the time-dependent electric and magnetic fields from a global magnetohydrodynamic simulation of this event to study the source of these ions and their acceleration. The simulation did a good job of reproducing the particle observations. Both solar wind protons and ionospheric oxygen were accelerated by nonadiabatic motion across large (>˜5 mV/m) total electric fields (both potential and induced). The acceleration occurred in the “wall” region of the near-Earth tail where nonadiabatic motion dominates over convection and the particles move rapidly across the tail. The acceleration occurred mostly in regions with large electric fields and nonadiabatic motion. There was relatively little acceleration in regions with large electric fields and adiabatic motion or small electric fields and nonadiabatic motion. Prior to substorm onset, ionospheric ions were a significant contributor to the cross-tail current, but after onset, solar wind ions become more dominant.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

A simulation study of particle energization observed by THEMIS spacecraft during a substorm 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 A simulation study of particle energization observed by THEMIS spacecraft during a substorm, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A simulation study of particle energization observed by THEMIS spacecraft during a substorm will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1193163

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.