In situ diagnostics of ionospheric plasma with the resonance cone technique

Abstract

Electron density and temperature profiles in the mid latitude ionosphere are derived from the ”resonance cone” in the radiation pattern of high‐frequency point antennas aboard a sounding rocket. By comparing the shapes for reversed wave propagation direction it is possible to study electron drift motion and field‐aligned beams. The data from the COREX‐I (Cooperative Resonance Cone Experiment) experiment show close agreement of electron density and temperature profiles from resonance cones with results from independent instruments. There was no indication of a substantial temperature anomaly at E region altitude during this flight. An unexpected electron drift can be interpreted as electron Hall current in the presheath of the negatively charged payload. Field‐aligned beams, which have been suggested in connection with the temperature anomaly, were not detected.

Electron temperature in nighttime sporadic E layer at mid-latitude

“…We now strongly believe that some heat source is still missing (Oyama and Hirao, 1980), that can elevate electron temperature higher than neutral temperature (Oyama, 2000;Rohde et al, 1993), or that the current theory on T e uses incorrect parameter values, such as suggested by Jain et al (1981) on the electron temperature in the equatorial electrojet. Further neutral density, which we usually take from MSIS, might differ from the real one (Kurihara and Oyama, 2005).…”

“…As the turbulent shadow is formed in opposition to the wind direction, ions have difficulty to be collected by the rocket surface, which faces in the opposite direction to the wind, due to the larger collision frequency between the ions and neutrals. Electrons can directly hit the rocket body along the magnetic field, because at the place where the electric field is radial to the rocket axis, electron does not experience an E×B drift around the rocket (Rohde et al, 1993). As ions are collected only by the surface area which faces the neutral wind, the rocket will become more negative in the strong neutral wind region.…”

Propagation and dispersion of electrostatic waves in the ionospheric E region

“…A source of uncertainty for the DC electric ®eld measurements is the variation in the local ®eld introduced by the rocket itself. These have been discussed by for instance Rohde et al (1993), but seem to be of importance only at the sheaths in vicinity of the body, not at the position of the boom-mounted probes.…”

Possible interaction between thermal electrons and vibrationally excited N<sub>2</sub> in the lower E-region

“…Almost without exception the surface of the electrode is contaminated. However even we remove the effect of electrode contamination or use the instrument which can avoid the electrode contamination (Hirao and Oyama, 1970;Oyama and Hirao, 1976), T e measured by DC Langmuir probe is higher than model T n (Oyama et al, 1980;Duhau and Azpiazu, 1985;Amemiya et al, 1985), although very rarely we observed T e which is very close to T n (Hirao and Oyama, 1973;Rohde et al, 1993).…”