2:15 PM - 2:30 PM
[PEM16-09] Sounding rocket experiment to clarify electron heating phenomena in the Sq current focus - Plasma wave observation -
Keywords:The sounding rocket experiment S-310-44, Sq current focus, Plasma wave observation, Lower hybrid resonance wave
During the flight, the following phenomena were identified: (1) Harmonic emissions of lower hybrid resonance (LHR) were found in a frequency range from several hundred Hz to several kHz. Their frequencies changes depending on the ambient plasma density and likely on the ion compositions. They are enhanced at altitude around 100 km in ascent but not enhanced at the same altitude in descent. (2) Upper hybrid resonance (UHR) waves were not found in a frequency range around several MHz. In most previous sounding rocket experiment, UHR waves were found in altitude range higher than 200 km, and masked at altitude below 200 km by the artificial radio waves from the ground. In this experiment, the artificial radio waves were not so intense to mask the other emissions.
The LHR waves can be generated by various energy inputs. Baker et al.  reported that LHR emissions were found in the sounding rocket experiment, and suggested that they are caused by the whistler waves from the thunderstorms on the ground. The enhancement of LHR only in ascent suggests that the energy source of LHR wave is localized in narrow area in E region of the ionosphere. Through the comparisons with data from the other instruments onboard the S-310-44 such as electron density and temperature (FLP), DC and AC electric fields (EFD), and currents (MGF), we will be able to discuss the energy source of the observed LHR waves in more detail.