2.3.3 Heterogeneous interactions at surfaces a Heterogeneous interactions are those which occur between different states of matter. most of these heterogeneous interactions involve wall bombardment by energetic free radicals, ions or electrons which can result in knocking electrons(secondary electron emission) or neutral atoms(sputtering or erosion) from the material of the wall a Recombination of ions and electrons when they reach a surface from plasma Promoting catalysis Deposition and coating of thin films because of a build up of particles or induced chemical reactions or polymerization on surface
2.3.3 Heterogeneous interactions at surfaces n Heterogeneous interactions are those which occur between different states of matter. Most of these heterogeneous interactions involve wall bombardment by energetic free radicals, ions, or electrons, which can result in knocking electrons (secondary electron emission) or neutral atoms (sputtering or erosion) from the material of the wall. n Recombination of ions and electrons when they reach a surface from plasma; n Promoting catalysis n Deposition and coating of thin films because of a build up of particles or induced chemical reactions or polymerization on surface
2. 3. 4 Plasma collisionality regimes a Lorentzian approach: electrons are assumed not to interact with each other, and the positive ions are considered to remain at rest a Krook model: a refinement of lorentzian gas, in which the effective collision time is independent of the particle momentum and energy
2.3.4 Plasma collisionality regimes n Lorentzian approach: electrons are assumed not to interact with each other, and the positive ions are considered to remain at rest. n Krook model: a refinement of Lorentzian gas, in which the effective collision time is independent of the particle momentum and energy
Boltzman -Vlasov model: suitable for the fusion regime a high temperature plasma for which the collisional mean free path is much larger than all of the characteristic lengths of the system Fokker-Planck model, in which the motion of a colliding particle in the velocity space of a fully ionized, highly turbulent, or electric field dominated plasma is determined by cumulative effect of weak deflections resulting from distant encounters, or fluctuating electric fields
n Boltzman-Vlasov model: suitable for the fusion regime, a high temperature plasma for which the collisional mean free path is much larger than all of the characteristic lengths of the system. n Fokker-Planck model, in which the motion of a colliding particle in the velocity space of a fully ionized, highly turbulent, or electric field dominated plasma is determined by cumulative effect of weak deflections resulting from distant encounters, or fluctuating electric fields
Homework Please give physical significances on these functions listed below wf(v)di 2 Please classify the heterogeneous interactions at surfaces
Homework: 1 Please give physical significances on these functions listed below: 2 Please classify the heterogeneous interactions at surfaces. ( )x f v 0 vf (v )dv
3 Motion of Charges in Electric and Magnetic Fields a An important difference between plasma and ordinary neutral gases is that plasma responds strongly to imposed electric and magnetic fields while neutral gases do not. This behavior of plasma is important in many industrial applications In order to better understand the behavior of plasma, it is necessary to review the interaction of individual charged particles and space charge of one polarity with electric and magnetic fields
3 Motion of Charges in Electric and Magnetic Fields n An important difference between plasma and ordinary neutral gases is that plasma responds strongly to imposed electric and magnetic fields, while neutral gases do not. This behavior of plasma is important in many industrial applications. n In order to better understand the behavior of plasma, it is necessary to review the interaction of individual charged particles and space charge of one polarity with electric and magnetic fields