Ds. Intriligator et Gl. Siscoe, STREAM INTERFACES AND ENERGETIC IONS CLOSER THAN EXPECTED - ANALYSES OF PIONEER-10 AND PIONEER-11 OBSERVATIONS, Geophysical research letters, 21(12), 1994, pp. 1117-1120
An empirical study of corotating interaction regions (CIRs) observed b
etween 3.9 AU and 5.9 AU on Pioneers 10 and 11 shows that the main cor
otation energetic ion population (CEIP), which is associated with the
trailing reverse shock, terminates within the CIR at a definite, struc
tural boundary, which we show here is the stream interface. This new r
esult has significant implications for solar wind and energetic partic
le modeling. In particular it implies either that the reverse shock fo
rms closer to the stream interface than models suggest or that the the
ories that treat the generation and transport of these energetic ions,
such as preshock Fermi acceleration and cross-field diffusion must be
combined or extended. We test these scenarios by comparing the CEIP i
ntensity profiles on the two sides of the stream interface. We find th
at while each automatically accounts for one or two aspects of the res
ults none of them alone can account for all of our empirical results.