secFieldEmitterSecondary particle emitter where the SEY (secondary yield) and emitted particle spectrum are defined by pair of Expressions (see Introduction to UserFuncs and Expressions). These Expressions are functions of primary velocity components (vperp, vpara), a scalar field (phi) and time (t). The secondary particles can be in the same species as the incoming electrons, or a separate species.
ptclAbsorber (string)Name of the absorber that absorbs the primaries and from which the secondaries will be emitted.
gridBoundary (string, optional)Name of a gridBoundary absorber that absorbs the primaries and from which the secondaries will be emitted.
Expression (block, required)An expression (see Introduction to UserFuncs and Expressions) that defines SEY. It must be
named SEYFunc. It can take four arguments vperp (primary velocity component along the surface normal, in m/s), vpara (primary velocity component parallel to the surface, in m/s), phi (the value of the scalar field at the location where the particle is absorbed) and t (time in second). Not all the arguments need to be used, but all arguments must come from
these four.
Expression (block, required)An expression (see Introduction to UserFuncs and Expressions) that defines secondary velocity
(beta) distribution.
It must be named SpectrumFunc and return a 3 component vector.
It can take four arguments vperp (primary velocity component along the surface normal, in m/s), vpara (primary velocity component parallel to the surface, in m/s), phi (the value of the scalar field at the location where the particle is absorbed) and t (time in second). Not all the arguments need to be used, but all arguments must come from these four.
The 3 component velocity vector returned is defined locally to the emitting surface. The first component is vnorm, which is along the surface normal (nvec) direction. The second component is along the direction of tvec = v x nvec, where v is the velocity vector of the incident primary particle. The third component is along the direction of nvec x tvec.
secondarySpecies (string, optional)Species name of the secondaries emitted. If this is not specified, the emitted particles are of the same species as the incident particle.
emittingSurface (float, optional)Physical position of the emitting surface in the direction of emission. If this parameter is not specified, it is calculated to be the appropriate edge of the grid. It is ignored when emitting from a grid boundary