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A new component of terrestrial radio emission observed from ISEE‐3 and ISEE‐1 in the solar wind
Author(s) -
Steinberg J.L,
Lacombe C.,
Hoang S.
Publication year - 1988
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl015i002p00176
Subject(s) - physics , interplanetary spaceflight , solar wind , interplanetary medium , radiation , scattering , astrophysics , astronomy , plasma , optics , nuclear physics
At a time when the AE index was 1300, the radio receivers on board ISEE‐3 (216 R E sunward of Earth) and ISEE‐1 recorded a new type of terrestrial radio emission between 20 and 50 kHz. The radiation had a smooth time profile, with a negative frequency drift; its angular diameter at 47 kHz was at least 170°. This smooth component followed the onset of a TKR burst whose angular diameter was 50° at the same frequency 47 kHz and varied as f −2 , i.e., was controlled by interplanetary scattering. Because of its time association with the TKR burst, the source of the smooth radiation must have been in the Earth environment. We suggest that it was produced or leaked into the interplanetary medium very far from Earth in order that the scattering path to ISEE‐3 be long enough (2000 R E ) to account for the observed angular diameter. More than 50 such events, clearly distinct from the Earth non thermal continuum, were observed between 1978 and 1983.