eV Kinetic Energy Research Articles

Possible contributions of fast neutral particles to the formation of the F2 layer

Due to a mean relative velocity of the order of 20 km/see between interstellar hydrogen and the sun interstellar gas succeeds in penetrating into the inner regions of the solar system. Fast neutrals of about 1000 eV kinetic energy will there be produced by charge exchange processes with solar wind protons. The effect on the ionosphere of those neutrals that are intercepted by the earth is studied. It is shown that above 300 km these neutrals constitute an additional ionization source besides the EUV radiation of the san. Its contribution to the total ionization at 1000 km is almost 25%. it diminishes to 4% at the height of the F2-layer maximum.

Ionisationsquerschnitt von OV gegenüber Elektronenstoß unter teilweiser Berücksichtigung des Austauschs

The ionization cross-section of highly ionized oxygen, O4+, is calculated according to the “distorted-wave” method. Exchange between the scattered and the ejected electron is taken into account as far as it is of long range nature. It is shown that contributions of high total angular momentum L are essential, L=0 giving only 3% of the total cross-section. This result should qualitatively be the same for all highly ionized atoms, whereas the following seems to be a special feature of O V ionization: for energies around twice the ionization energy the contributions of the optically allowed transitions of the ejected electron (angular momentum lej=1) are relatively small. The contributions of lej =0, 1, 2 and 3 are about 16%, 18%, 24% and 19% respectively for E=20.13.6 eV=2.39 × Ionization energy. The maximum cross section is 0.112 at. u. = 0.31 ·10-18 cm2 for electrons of 310 eV kinetic energy (2.8 × ionization energy). It is about twice as large as given by the ELWERT formula.