Shape Settable Flux Emitter¶
All particle types may emit from a shape settable flux emitter. Certain emission specifications are only available based on particle type and particle weights specification. Available in cartesian coordinate simulations only.
- start time
Time to start emitting particles.
- stop time
Time to stop emitting particles.
emission specification: Specification of the emitted particles, note that the specification options vary for constant or variable/managed weight particles.
- emission current density:
Only available with variable/managed weight specified particles.
emission current density: Specify the current density of the emitter (amps/meter^2). Can be a spatial profile.
velocity coordinate system: Either global or surface. A global coordinate system will specify the emission velocities according to global axis. A surface coordinate system will set the emission directions according to the normal of the emission object. A positive value will emit particles away from the shape and a negative value will emit particles into the shape.
average velocity 0: The average (mean) speed of particles in the x-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for the direction normal to the emitting surface.
average velocity 1: The average (mean) speed of particles in the y-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
average velocity 2: The average (mean) speed of particles in the z-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
thermal velocity 0: A spread (standard deviation) for particle speeds in the 0 direction.
thermal velocity 1: A spread (standard deviation) for particle speeds in the 1 direction.
thermal velocity 2: A spread (standard deviation) for particle speeds in the 2 direction.
- emission flux:
Only available with variable/managed weight specified particles.
emission flux: Specify the flux of the emitter (particles/meter^2). Can be a spatial profile.
velocity coordinate system: Either global or surface. A global coordinate system will specify the emission velocities according to global axis. A surface coordinate system will set the emission directions according to the normal of the emission object. A positive value will emit particles away from the shape and a negative value will emit particles into the shape.
average velocity 0: The average (mean) speed of particles in the x-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for the direction normal to the emitting surface.
average velocity 1: The average (mean) speed of particles in the y-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
average velocity 2: The average (mean) speed of particles in the z-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
thermal velocity 0: A spread (standard deviation) for particle speeds in the 0 direction.
thermal velocity 1: A spread (standard deviation) for particle speeds in the 1 direction.
thermal velocity 2: A spread (standard deviation) for particle speeds in the 2 direction.
- emission current:
Only available with constant weight particles.
emission current: Specify the total emitted current per second from the emitter (amps/second).
velocity coordinate system: Either global or surface. A global coordinate system will specify the emission velocities according to global axis. A surface coordinate system will set the emission directions according to the normal of the emission object. A positive value will emit particles away from the shape and a negative value will emit particles into the shape.
average velocity 0: The average (mean) speed of particles in the x-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for the direction normal to the emitting surface.
average velocity 1: The average (mean) speed of particles in the y-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
average velocity 2: The average (mean) speed of particles in the z-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
thermal velocity 0: A spread (standard deviation) for particle speeds in the 0 direction.
thermal velocity 1: A spread (standard deviation) for particle speeds in the 1 direction.
thermal velocity 2: A spread (standard deviation) for particle speeds in the 2 direction.
- emission rate:
Only available with constant weight particles.
emission rate: Specify the total emitted particles per second from the emitter (particle/second).
velocity coordinate system: Either global or surface. A global coordinate system will specify the emission velocities according to global axis. A surface coordinate system will set the emission directions according to the normal of the emission object. A positive value will emit particles away from the shape and a negative value will emit particles into the shape.
average velocity 0: The average (mean) speed of particles in the x-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for the direction normal to the emitting surface.
average velocity 1: The average (mean) speed of particles in the y-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
average velocity 2: The average (mean) speed of particles in the z-direction when velocity coordinate system is set to “global”. If set to “surface” then this will be the average velocity for a direction perpendicular to the emitting surface.
thermal velocity 0: A spread (standard deviation) for particle speeds in the 0 direction.
thermal velocity 1: A spread (standard deviation) for particle speeds in the 1 direction.
thermal velocity 2: A spread (standard deviation) for particle speeds in the 2 direction.
- Fowler Nordheim Emission:
Specify particle emission according to the Fowler-Nordheim model (24). Only available with variable/managed weight electron particle species.
work function [eV]: Work function of the material from which emission is occurring.
A: Coefficient A of the Fowler-Nordheim emission model.
B: Coefficient B of the Fowler-Nordheim emission model.
field enhancement: Multiplies the measured electric field by this amount.
Cv: Coefficient Cv of the Fowler-Nordheim emission model.
Cy: Coefficient Cy of the Fowler-Nordheim emission model.
- Richardson Dushman Emission:
Specify particle emission according to the Richardson-Dushman model (22). Only available with variable/managed weight electron particle species.
work function [eV]: Work function of the material from which emission is occurring. Parameter in the Richardson-Dushman model.
field evaluation offset: The offset from the surface where the field resulting from the particle is evaluated.
temperature (K): Temperature of the material from which emission is occurring. Parameter in the Richardson-Dushman model.
field enhancement: Multiplies the measured electric field by this amount.
flux multiplier: Multiplies the resulting output current by this amount.
- Child Langmuir Emission:
Specify particle emission according to the Child Langmuir model. Only available with variable/managed weight electron particle species.
space charge limited emission: This will limit the current to provide a more consistent emission current, providing higher accuracy particularly in explosive emission cases, such as a pulsed power magnetron. For non pulsed-power simulations it is not necessary.
average velocity 0: The average (mean) speed of particles in the 0 direction.
average velocity 1: The average (mean) speed of particles in the 1 direction.
average velocity 2: The average (mean) speed of particles in the 2 direction.
thermal velocity 0: A spread (standard deviation) for particle speeds in the 0 direction.
thermal velocity 1: A spread (standard deviation) for particle speeds in the 1 direction.
thermal velocity 2: A spread (standard deviation) for particle speeds in the 2 direction.
- emission surface
The surface off of which to emit.
object name: The name of the geometry off of which to emit.
emission offset: The distance away from the object that emitted particles are placed, as a fraction of a cell length.
- macroparticle emission:
Only available with variable/managed weight particles. This allows for the specification of the macroparticle emission independent of the emitted particles. Used to handle computational concerns around macroparticle weight.
- macroparticle rate:
Number of macroparticles to emit per timestep. This value can be modified by the macroparticle emission profile.
- macroparticle emission profile:
Spatial profile for emission of the macroparticles. If this corresponded to half of the emissions shape, half of the number of macroparticles specified in macroparticle rate would be emitted, while the emission specification would be unaffected.