A large increase of electron density in ionospheric heating experiment

The high latitude ionospheric heating experiment was carried out with the EISCAT high power heating and diagnosing facilities in November 2011 in Norway. An obviously increased electron density was observed by UHF radar. The increase is up to 269. 3% above the background level around the reflection height, and it could reach 30%similar to 50% at the altitude range of 300 similar to 500 km far away from the heater interaction region. The increased electron density observed at 300 similar to 500 km is verified by the analysis of ion lines and residual error in this experiment. To the authors' knowledge, the large increase of electron density in such a large range of space is extremely rare. In addition, a double-peaked spectrum is observed in plasma lines. The plasma lines are simulated based on the relationship between the electron velocity distribution function and the plasma line spectrum, and the large increase of electron density in this experiment may be caused by suprathermal electrons. The ionization ability, horizontal and vertical free path of suprathermal electrons are calculated using the velocity parameters used in the plasma lines simulation, and the hypothesis is proved to be reliable.