Singly-ionized helium in the driver gas of an interplanetary shock wave

The interplanetary shock wave observed on Jan. 29, 1977 by the HELIOS-1 plasma instruments shows an unusual feature: In the cold tenuous piston plasma following this shock, there appears a third peak in the energy per charge (E/q) spectra, in addition to the normal proton and α-particle peaks. the peak is located at E/q=4 and persists for about 14 hours, with slowly varying intensities. Independent simultaneous measurement of these particles' charge yields a value of approx. =1. These ions are thought to be 4He+ ions travelling with the same speed as protons and α-particles. The occurrence of 4He+ indicates the possibility that during eruptive prominences or other solar transients ''cold'' chromospheric plasma might escape from the sun without undergoing the normal coronal heating process