neutrals are set by the balancing of all processes for energy gain and loss, and the RF beam is a noteworthy contributor. The electron heating rate Q per unit volume in the beam is proportional to several factors: To determine the dominant loss processes for electron heat energy, one must consider details of the atmospheric composition, the relevant collision cross sections, and the interplay of mean free path, thermal conduction, and magnetic confinement. Recently, Perkins and Robie (1978) (hereinafter PR) have numerically evaluated the resultant effects of these processes in standard midlatitude atmospheres with typical RF heating. They point out the comparabi1ity of effects from the low-frequency Arecibo antenna (15 MHz, 1 to 3 MW) and from a possible satellite power station (2.45 GHz, 10 GW). In the low D and E regions, the heated free electrons lose energy mostly by collisions exciting rotational and vibrational states of the major moelcules and O^. Since these homonuclear molecules cannot radiate the energy, it is collisionally transferred to and emitted by C02 (4.3 p) and H20 (6.5 p), respectively. Throughout the E region the abundant atomic 0 provides for electron energy loss by the excitation of fine structure levels in ground state 3 0( P). Also, Coulomb collisions of electrons and ions are significant. In the more highly ionized F region, principal electron energy degradation is by electron Coulomb collisions and by electron-spin exchange collisions producing metast- able 0( D) and its subsequent 6300A emission. A list of the above follows:
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