INITIAL OBSERVATIONS OF VLF ELECTRIC AND MAGNETIC FIELDS WITH THE INJUN 5 SATELLITE.
IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY
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The Injun 5 satellite, launched into a low altitude 677 to 2528 km polar orbit on August 8, 1968, carried a very-low-frequency VLF electric and magnetic fields experiment covering the frequency range from DC to 105 kHz for electric fields and 30 Hz to 10 kHz for magnetic fields. This paper describes the VLF experiment and presents initial results of immediate interest. Broad-band 30Hz to 10kHz electric field intensities are found to be remarkably small, typically less than 100 microvoltmeter and seldom greater than 1 mvoltmeter. Most of the common types of VLF electromagnetic noise, electron and proton whistlers, chorus, ELF hiss, VLF hiss, and periodic emissions, have been observed simultaneously with both the electric and magnetic antennas, thus providing an excellent check on the operation of the electric antenna. Phase measurements between the electric and magnetic fields have been used to determine the direction of propagation, up or down the geomagnetic field. New phenomena observed include 1 spin modulation of lower hybrid resonance noise, 2 multiple frequency noise bands possibly related to lower hybrid resonance noise, 3 a narrow bandwidth electric field enhancement near the two-ion cutoff frequency, and 4 noise bands associated with harmonics of the proton gyrofrequency. Author
- Atmospheric Physics