Measurements of the intensity and spectrum of electrons at 1000-kilometer altitude and high latitudes
The intensity and spectrum of electrons at lOOO-km altitude were measured by detectors on the SUl satellite Injun I at magnetic latitudes between about 45 and 80 deg . A preliminary report is given for July and August 1961. Trapped electrons above 40 kev were found between 45 and about 75 deg 10/sup 5/ to 10/sup 6/ particles (cm/sup 2/ sec ster)/sup -1/, wiyth peak intensity 4 x 10/ sup 6/ particles (cm /sub 2/ sec ster)/sup -1/. The intenslty above 75 deg was less than 10/sup 2/ particles (cm/sup 2/ sec ster)/sup -1/. Occasionally the electron intensity reached a broad peak around 50 deg and a second peak near the auroral zone. The intensity in the second region often varied by an order of magnitude in times of a few seconds or distances of a few tens of kilometers. lf the differential electron spectrum followed a power law of the usual form dN = constant E-V dE, then, for both trapped and dumped electrons 40 to 120 kev, GAMMA varied significantly between 0 and 2 below 60 deg , and between 0 and 7 at latitudes above 60 deg . The spectrum was generally softer at higher latitudes. In the daytime, electrons above I kev were observed in fluxes of the order of 10 ergs (cm/ sec ster)/sup -1/ at such angles to the magnetic field vector that they must have penetrated to auroral altitudes of 200 plus or minus 200 km. Since they could produce weak auroras, it is concluded that auroras can occur in the daytime. Since they were detected at 1000-km altitude, it is concluded that an acceleration mechanism in the ionosphere is not always necessary to produce an aurora in the same hemisphere. The measurements are compared with other satellite, rocket, and balloon measurements. Most of the counts of the type 302 shielded Geiger tube in Explorer VII were due to penetrating particles, likely electrons at several Mev in peak intensity of order lD3 particles (cm/sup 2/ sec)/ sup -1/. The significance of the latitude distribution of the low-energy electron fluxes is discussed.
- Research Organization:
- State Univ. of Iowa, Iowa City
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-16-018293
- OSTI ID:
- 4841162
- Journal Information:
- Journal of Geophysical Research, Vol. 67, Issue 4; Other Information: Orig. Receipt Date: 31-DEC-62; ISSN 0148-0227
- Publisher:
- American Geophysical Union
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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