Artificial small-scale field-aligned irregularities in the high latitude ionosphere F region: Comparison between O-and X-mode HF pumping at EISCAT

We present experimental investigations of distinctive features and behaviors of artificial small-scale fieldaligned irregularities (AFAIs) in the high latitude ionosphere F-region induced by the ordinary (O-mode) and extraordinary (X-mode) polarized HF pump waves. Results are based on a large body experiments carried out at the EISCAT HF heating facility at Tromsó Norway from 2010 – 2019.