Polar jet kinetics and energetics analysed from STEREO/COR data

Feng Li, Purple Mountain Observatory, CAS, China
Inhester Bernd, Max Planck Institute for Solar System Research, Germany
Gan Weiqun, wqgan@pmo.ac.cn, Purple Mountain Observatory, CAS, China

Abstract
We analyze coronagraph observations of a polar jet eruption observed by the SECCHI instrument suite on board the STEREO spacecraft. In our analysis we compare the brightness distribution of the jet in white-light coronagraph images with a kinetic particle model. In this first application, we consider only gravity as the dominant force on the jet particles along the magnetic field. We find that the kinetic model explains well the observed brightness evolution. The derived initiation time is consistent with the jet observations by the EUVI telescope at various wavelengths. The initial particle velocity distribution is fitted by Maxwellian distributions and we find deviations of the high energy tail from the Maxwellian distributions. We have estimated the jet’s total electron content to a mass between 3.2 ? 10^14 and 1.8 ? 10^15 g. The total kinetic energy of all the particles in the jet source region amounts from 2.1 ? 10^28 to 2.4 ? 10^29 erg. Mapping the integrated particle number along the jet trajectory to its source region and assuming a typical source region size, we obtain an initial electron density between 8 ? 10^9 cm^?3 and 5 ? 10^10 cm^?3. It implies that the magnetic energy was predominantly released in the lower corona or the upper chromosphere.