Ions A++B→→A+B+ Charge exchange A++B→→A++B Elastic scattering A++B→A+B++e lonization A++B→A++B*→A++B+ hy Excitation A++e+B→A+B Recombination A++BC→A++B+C Dissociation A+BC-C+AB Chemical reaction
Ions A+ +B→A+B+ Charge exchange A+ +B→A+ +B Elastic scattering A+ +B→A++B++e Ionization A+ +B→A+ +B* → A++B+hν Excitation A+ +e+B→A+B Recombination A+ +BC→A+ +B+C Dissociation A +BC→C+AB Chemical reaction
2.3. 1 Elastic binary collisions a Binary collisions: collisions involving only two particles in gas or plasma a Elastic binary collisions the total kinetic energy of the two particles is conserved a Inelastic binary collisions the initial kinetic energy of the two colliding particles is greater than the kinetic energy after the collision
2.3.1 Elastic binary collisions n Binary collisions:collisions involving only two particles in gas or plasma n Elastic binary collisions:the total kinetic energy of the two particles is conserved. n Inelastic binary collisions:the initial kinetic energy of the two colliding particles is greater than the kinetic energy after the collision
a Binary collisions between charged particles, i. e between two electrons, two positive ions, or ions and electrons are irrelevant in the industrial applications of plasma because a In most industrial plasmas the degree of ionizations is generally quite low, the dominant collisional process is between charged particles and the neutral background gas----------Lorentzian gas
n Binary collisions between charged particles, i.e. between two electrons,two positive ions,or ions and electrons are irrelevant in the industrial applications of plasma because: n In most industrial plasmas the degree of ionizations is generally quite low,the dominant collisional process is between charged particles and the neutral background gas----------Lorentzian gas
2.3.2 Inelastic binary collisions a When two particles undergo an inelastic binary collision, their kinetic energy is less after the collision than it was prior to it One such process is the excitation of a neutral atom by the energetic charged particles a If the neutral gas consists of molecules dissociation can occur in which collisions with energetic ion or electron will break up a molecule into one or more of its constituent parts
2.3.2 Inelastic binary collisions n When two particles undergo an inelastic binary collision, their kinetic energy is less after the collision than it was prior to it. n One such process is the excitation of a neutral atom by the energetic charged particles. n If the neutral gas consists of molecules, dissociation can occur, in which collisions with energetic ion or electron will break up a molecule into one or more of its constituent parts
a Ionizing collision, in which one or more electron is stripped away from the atom or molecule aA charged-exchange collision results in exchanging an electron between a cold neutral atom or molecule and an energetic ion in plasma Finally, if a partially ionized plasma is of atmospheric or greater density, significant recombination can occur. Recombination must be a three-body process
n Ionizing collision, in which one or more electron is stripped away from the atom or molecule. n A charged-exchange collision results in exchanging an electron between a cold neutral atom or molecule and an energetic ion in plasma. n Finally, if a partially ionized plasma is of atmospheric or greater density, significant recombination can occur. Recombination must be a three-body process