Effects of the angle between the density gradient and the external

We study the effect of the angle between the density gradient and the external magnetic field on the efficiency of the linear mode conversion and the resultant beaming angle of converted LOmode waves. We first consider a condition that the density gradient is perpendicular to the external magnetic field, corresponding to the condition assumed in the conventional LMCT. Next, we extend the discussion to the condition that the density gradient is oblique to the external magnetic field. Our aim here is to investigate a condition where the efficient mode conversion can occur and to study the deviation of the beaming angle from that estimated by LMCT. In the results of analyses, the highest conversion efficiency is obtained under the specific condition of the wave normal angle of the incident UHR-mode waves for both perpendicular and oblique cases. The simulation results show in the perpendicular case the beaming angle is consistent with the conventional LMCT. However, we show in the oblique case a critical wave normal angle becomes different from the perpendicular case and the beaming angle is different from the LMCT prediction.