IMP-8 observations of traveling compression regions - New evidence for near-earth plasmoids and neutral lines

An examination of IMP-8 tail lobe magnetic field measurements has been conducted to determine whether the traveling compression region (TCR) phenomena detected by ISEE-3 in the distant geotail, and believed to be caused by tailward moving plasmoids, are present closer to the earth. The study produced 16 examples of TCRs at distances of X = -31 to -37 R(E). For two events considered in detail, TCRs were observed in close association with substorm growth phase signatures in the lobes. The lengths of these TCRs are estimated to be 8-12 R(E). The conclusion is that the IMP-8 TCR observations provide new evidence that small plasmoids and, hence, multiple reconnection neutral lines can sometimes exist earthward of X = -35 R(E).