Fig. 2
From: Statistical study of PMSE response to HF heating in two altitude regions
An example of heater induced PMSE modulation and layers on July 13, 2007, observed by the EISCAT VHF radar. The heater-on time is shown by the green rectangles at the bottom. The HF transmitter was operated with X-mode for the first 30 min (11:00–11:30 UT) and with O-mode for the last 30 min (11:30–12:00 UT). At both modes, the frequency of transmitter was 5.423 MHz