Dispersion calculation for lower hybrid waves in the current sheet of reconnection with guide field

Lower hybrid waves have been observed in the current sheet during reconnection with guide field in both the Magnetic Reconnection Experiment (MRX) and Magnetospheric Multiscale (MMS) mission. The observed waves produce density fluctuations correlated with electric field, generating anomalous resistivity. To understand the excitation mechanism and propagation of the lower hybrid waves, the dispersion relation and growth rate will be calculated by a linear calculation [Ji et al. 2005]. In this local calculation, both parallel and perpendicular electron flows exist in the ion rest frame. Based on the measured value of the phase velocity, which is comparable to the ion thermal speed, it is important to include ion thermal effects in the calculation. We use the J-pole expansion of the plasma dispersion function to capture ion thermal effects in the dispersion relation. Results with ion thermal effects will be compared with those from the cold ion limit.