Problems and Concept Questions

The Marrone-Treanor parameter U is constant only overa narrow range of temperatures. Details about two-temperature dissociation kinetics for To TV can be found in Sergievska, Kovach, Losev (1995). 

Coulomb Collisions. Using integral relation (2-7), try to calculate the rate coefficient for electron-electron Coulomb collisions in plasma with electron temperature = eV. Assume the Maxwellian distribution function (2-1) for plasma electrons and take expression (2-8) for the Coulomb collisions cross section. Analyze the contribution of slow and fast electrons in the Coulomb collision reaction rate. 

Ionization by Direct Electron Impact, Thomson Formula. Compare cross sections of the direct ionization by electron impact calculated using different modifications of the Thomson formula (2-11), (2-13), and (2-14). Calculate the maximum values of the cross sections and corresponding values of electron energy for each of the Thomson formula modifications. 

Stepwise Ionization by Electron Impact. Estimate a stepwise ionization rate coefficient in Ar at electron temperatures of 0.5 and 1 eV, assuming quasi-equilibrium between plasma electrons and electronic excitation of atoms. Comment on why the stepwise ionization is a preferential one in thermal plasmas and less important in non-thermal discharges. 

Ionization in Collisions of Heavy Particles. Estimate the adiabatic Massey parameter and ionization probability and cross section for ionization of an Ar atom at rest in collision with an Ar+ ion having kinetic energy twice that of the ionization potential. Compare the ionization probability in this case with the one for the Penning ionization. 

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