First pulsed radio soundings of the topside of the ionosphere

Abstract

At 1817 75°W time on June 24, 1961, a two‐frequency pulsed radio sounder (ionosonde) was carried to an altitude of about 1060 km, east of Wallops Island, Virginia, by means of a fourstage, solid‐propellant rocket (NASA 8.15). Reflections from the topside of the ionosphere were obtained on one or both frequencies during 13 minutes of the flight. The objective of the experiment was to test the sounding system that is to be used in a satellite‐borne, fixed‐frequency topside sounder scheduled to be placed in orbit in 1962. The purpose of this short communication is to present the topside soundings obtained during the flight and to describe some preliminary results of the experiment.

Plasma wave observation and sounder experiments(PWS) using the Akebono (EXOS-D) satellite. Instrumentation and initial results including discovery of the high altitude equatorial plasma turbulence.

“…In the study of high frequency plasma wave observations in space plasma, the contributions of the research based on IMP, GEOS, Hawkeye, ISIS-1, EXOS-B and DE satellites have provided very prominent results, including new evidence of auroral kilometric radiations (GURNETT, 1974;KURTH et al, 1975;KAISER and STONE, 1975;BENSON, 1975BENSON, , 1982ALEXANDER and KAISER, 1977;KAISER et al, 1978;BENSON and CALVERT, 1979;BENSON et al, 1980;JAMES, 1980;CALVERT, 1981;OYA et al, 1981;MORIOKA et al, 1981;MORIOKA, 1981, 1983;GURNETT et al, 1983). In parallel to the studies on these passive observations of plasma waves, there is another long history of active experiments on the plasma waves, starting from experiments by sounders on board rockets, Alouette 1, 2 and ISIS-1 satellites (KNECHT et al, 1961;LOCKWOOD and NELMS, 1964;NELMS and LOCKWOOD, 1967;JACKSON and WARREN, 1969;FRANKLIN and MACLEAN, 1969;HAGG et al, 1969).…”

Pulsed radio soundings of the topside of the ionosphere in the presence of spreadF

“…The objectives of the rocket program were to test the feasibility of the method and the instrumentation, to permit optimization of design parameters, and to facilitate planning of the reduction of the satellite data. The preliminary results of the first (NASA 8.15), fired into a quiet ionosphere at 1817 75øW time on June 24, 1961, have already been reported [Knecht, Van Zandt, and Russell, 1961]. The purpose of this note is to report the initial results of the second topside sounder firing, designated NASA 8.17, which took place at the NASA Wallops Island station at 2326 75øW time on October 13, 1961, during a time when moderate spread F was being observed with a ground-based ionosonde.…”

High‐frequency magnetospheric sounding at EISCAT: Some trials and their implications

“…A method which is known to work relies on guidance of the electromagnetic wave by geomagnetic field-aligned plasma density irregularities or ''ducts''. This phenomenon is perhaps best-known from satellite topside sounder measurements [Knecht et al, 1961;Muldrew, 1963Muldrew, , 1967Muldrew, , 1980Muldrew, 1973, 1975] but can also be observed on the ground [Bukin, 1978;Gurevich and Tsedilina, 1985;Ellis and Goldstone, 1987, 1988, 1990. Once the wave enters such a duct, it is guided along it until the plasma density becomes sufficiently high to reflect it back along the duct, or sufficiently weak that it leaves the duct again.…”