Relation between lower ionospheric electron density profiles and cosmic noise absorption during auroral zone disturbances.

Abstract

Eight rockets among a total of twenty-one rocket experiments by the 12th, 13th and 14th Japanese Antarctic Research Expedition parties were launched during auroral disturbances at night at Syowa Station, Antarctica between 1971 and 1973. The electron density profiles in the lower ionosphere between about 50 km and 130 km under various disturbed conditions were obtained by rocketborne radio frequency probes and electrostatic probes.The collision frequency profile is derived from the electron density profiles and cosmic noise absorption measurements.There exists a maximum absorption layer in the region between 75 km and 85 km, and this location of the layer is not strongly dependent on the magnitude of the ionospheric dis-turbance. An increase in the electron density, especially in the D and E region between about 75 km and 110 km has a good correlation with cosmic noise absorption; the following empirical formulae are obtained from the observational results: , hm-2x+100, where 4n6(cm-3) is the maximum increment of the electron density from the quiet level, hm(km) is the height of the maximum increment of the electron density and x (dB) is the cosmic noise absorption.

A new method for deducing the effective collision frequency profile in the D‐region

“…[63] The corrected collision frequency profiles (Figure 7) are in close agreement with the results of Miyazaki [1975] from a geographic latitude of 69°00 0 S. This is close to the southern hemisphere latitude corresponding to Tromsø (69°35 0 N), and confirms that the log linear altitude dependence assumed by Miyazaki [1975] is a reasonable approximation in the high-latitude D-region.…”

“…[4] Previously, Miyazaki [1975] obtained a collision frequency profile by combining eight rocket-measured electron density profiles of the Antarctic D-region, with corresponding ground-based cosmic noise absorption measurements. By assuming a log linear altitude dependence, the least squares method was employed to give a collision frequency profile of the form n = n 0 exp(Àh/H), where h is the height above ground level and H is the scale height.…”

Full wave calculation method of VLF wave radiated from a dipole antenna in the ionosphere‐analysis of joint experiment by HIPAS and akebono satellite

“…At the points z = %+ and z = q-, the direct waves from the source can be obtained from Eqs. (12), (14), (15), and (16). They are allowed to be Zs(Sx.…”

“…Hence, the electron density model used in the calculations was created as follows. Since the aurora was generated in the lower ionosphere up to the altitude of 100 km, the results measured by the S-210JA-18 rocket (Aurora model) [15,161 launched by the 14th South Pole Expedition Team were used. For the foregoing region, the IRI model was used so that the results are connected to the electron density (N, = 1.9 x lo3) [l] at the satellite altitude obtained by the PWS (high-frequency region plasma wave and sounder experiment).…”