Ionization state of plasma bunches generated by collisions of dust particles and the charge of plasma ions of cometary atmospheres

The ionization state of plasma bunches arising in collisions between dust particles of cometary atmospheres and interplanetary-dust particles is described by the Saha equation at comet heliocentric distances (R) not less than 0.3 AU and by the Elvert equation at R not greater than 0.3 AU. These equations are used to obtain the dependence of the ion charge of the plasma bunches on R, and it is shown that the multiplicity (z) of this charge is greater than about 5 at R not greater than 1 AU. It is concluded that these factors must be taken into account in the calculation of the expected intrinsic X-ray emission of comets because of the collisions of cometary and zodiacal dust particles, and in the study of the ionization of cometary atmospheres.