[PEM11-P12] Flow speed dependence of ion temperature, electron temperature, and their ratio in the near-Earth magnetotail reconnection region
Keywords:temperature ratio, flow, MMS
In this study, we examine the relation between flow speed and average profiles of Ti, Te, and Ti/Te in the magnetotail reconnection region by using data obtained from FPI and FGM on board the MMS spacecraft. We use the observations for a period from May to August 2017 and take out the data in the region of XGSM < -15 Re, -10 Re < YGSM< 10 Re, and beta > 0.1. We then divide them into different groups according to flow speed normalized by alfven speed and show Bz/Blobe– Bx/Blobe maps of Ti, Te, and Ti/Te of each group.
The results show that ion temperature increase with increasing flow speed while electron temperature decrease. Ion temperature are hotter around the X-point. The structure of inflow and outflow regions is pronounced in the profile of electron temperature. Ti/Te in inflow region are greater than in outflow region, which means that ion and electron temperatures become comparable by passing through the diffusion region. The results suggest that electron get less energy when more energy is partitioned into plasma kinetic energy. We will discuss about the profiles of anisotropy of plasma temperatures to know more details about the heating mechanisms.