Anomalously low proton temperatures in solar-wind following interplanetary shock waves, evidence for magnetic bottles

A large fraction of such measurements by the Vela 3 satellites follow the passage of interplanetary shocks by some 20–60 hours. Of 24 postshock events in which Ï exceeded 400 km sec−1 and for which Vela 3 measurements are available, 12 exhibited plasma states of anomalously low Tp, high Ï .

The proton density at the time of these observations typically was depressed below normal, and the velocity tended to be constant or falling. A very strong association with abnormally high (≥15%) concentrations of He++/H+ in the solar wind is noted for these anomalous proton temperatures, the usual temporal sequence of events at 1 AU being: (1) shock wave, (2) helium enrichment, and (3) low Tp, high Ï . It is suggested that these observations are consistent with a model for some shock wave disturbances that includes the ejection of new material (distinguished by the helium enrichment at 1 AU) into the solar wind at the time of large solar flares and the formation of a magnetic bottle configuration in the solar wind behind and within the ejecta.