A proposed electrostatic acceleration mechanism in the upper atmosphere and its bearing on the helium problem

Escape of atmospheric helium by nonthermal processes

“…Acceleration by an electric field. Wilson [1962] has proposed an escape mechanism based on the accelera(•ion of tie • ions by an ambient atmospheric electric field. The basic idea is that Itc • ions are cumulatively accelerated between elastic collisions with atomic oxygen, the charge exchange reaction (whose cross sec½ion may be very much smaller than the elastic collision cross Marno (unpublished report, Boulder, Colorado, 1966), Smith a•d $ayer [1964], Moran and Friedman [1966], and Maier [1968].…”

The polar wind and the terrestrial helium budget

“…We conclude, therefore, that the escape mechanism must be nonthermal and must not favor sig- It has been pointed out by Nicolet [1961] that the total rate of photoionization of atmospheric/-/e • by solar ultraviolet is approximately the same as P(He•), and hence that some process involving helium ions might provide the explanation of the escape of both /-/e • •nd He • from the atmosphere. Several mechanisms involving ions have been proposed [Wilson, 1962; Bates and Patterson, 1962] but found inadequate (Patterson, unpublished). In each case the particles were assumed to escape eventually as neutral atoms, since it was thought that ions would remain trapped in the geomagnetic field even if they are given sufficient energy to escape from the gravitational field (1.8 ev for He 8 and 2.4 ev for He•).…”

Geophysical implications of the excess helium found in Pacific waters

“…A different and equally ingenious approach to the nonthermal acceleration of helium, also based on the presence of helium ions, has been suggested by Wilson [1962]. Wilson argues that charge separation in the upper atmosphere by differential penetration of eorpuseular beams may lead to electric fields, in which He + would pick up energy in a radial direction, until they undergo a collision with another atom.…”