Propagation and absorption of waves at the lower hybrid resonance

A simple and accurate approximation to the electrostatic hot plasma dispersion relation in the region of the lower hybrid resonance is obtained, using the fact that omega >> Omega ci and k perpendicular to nu thi / Omega ci >>1 in this region. The approximate dispersion relation is shown to reduce to the warm plasma approximation when also omega /k perpendicular to nu thi >>1, and gives explicit expressions for the damping length. It is particularly appropriate for rapid numerical calculations of the dispersion curves.