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Observations of two distinct populations of bow shock ions in the upstream solar wind
Author(s) -
Gosling J. T.,
Asbridge J. R.,
Bame S. J.,
Paschmann G.,
Sckopke N.
Publication year - 1978
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/gl005i011p00957
Subject(s) - magnetosheath , solar wind , ion , bow shock (aerodynamics) , physics , bow wave , spectral line , population , shock (circulatory) , plasma , atomic physics , shock wave , astrophysics , astronomy , magnetopause , nuclear physics , medicine , quantum mechanics , demography , sociology , thermodynamics
Observations upstream of the earth's bow shock with the LASL/MPI fast plasma experiments on ISEE 1 and 2 reveal the presence of two distinct and mutually exclusive populations of low energy (≤ 40 keV) ions apparently accelerated at the bow shock. The first of these, the "reflected" population, is characterized by 1) sharply peaked spectra seldom extending much above ∼ 10 keV/ion and 2) relatively collimated flow coming from the direction of the shock. On the other hand, the "diffuse" ions are distinguished by relatively flat energy spectra above ∼ 10 keV and broad angular distributions. They are by far the most commonly observed upstream ion event. A close causal association is suggested between the diffuse ion population in the upstream solar wind and energetic plasma ions observed within the magnetosheath.