Parameter definitions for "drude"
It's probably useful to look first at the special features page. You may also want to look at one of the general help files, Sliders, or
Graphs.
Inputs
- SLIDERS
- E_x: x-component of an applied electric field, in units of 10^4 V/m.
- E_y: y-component of an applied electric field, in units of 10^4 V/m.
- B_z: magnitude, in tesla, of a magnetic field applied perpendicular to the xy-plane in which the electrons move
- tau: electron scattering time, in picoseconds, in the Drude model. The scattering is isotropic and inelastic: after a scattering the electron is given a new velocity consistent with a Maxwellian distribution characterized by the temperature. (Restricted to positive values.)
- temperature: the temperature, in kelvin, of the Maxwellian distribution used for the initialization and scattering routines. (Restricted to positive values.)
- omega: the angular frequency, rad/s, of the electric field. Omega should be set to zero for a DC field.
- phase: phase, in radians, of the y-component of an AC field relative to the x-component. Phase = 0 gives linear polarization, and Phase = [+ (or -)](pi/2) gives right (or left) circular polarization of the E-field. The red bar in the velocity display illustrates the time dependence of the E-field.
- speed: changes the speed of the animation. For slow speeds the animation speed is proportional to the speed control, but saturates to a fixed rate at the higher speeds. (Restricted to positive values.)
- MENUS
- show(position): allows the position graph to display:
- average: average position of the ensemble of electrons as a function of time.
- deviation: mean square deviation of the electron positions from their average.
- show(velocity): allows the velocity graph to display:
- average: average velocity of the ensemble of electrons as a function of time.
- deviation, mean square deviation of the electron velocities from their average.
- TOGGLES
- run/stop: starts and stops (but does not initialize) the simulation. Key equivalent is the spacebar.
- show graph(position): opens and closes the graph showing the time dependence of the average and mean square deviations of the electron positions. The blue line is the x-component, the green line the y-component. The red line gives the time dependence of the E-field in arbitrary units: useful only as a phase reference with an AC field.
- show graph(velocity): opens and closes the graph showing the time dependence of the average and mean square deviations of the electron velocities. The blue line is the x-component, the green line the y-component. The red line gives the time dependence of the E-field in arbitrary units: useful only as a phase reference with an AC field.
- BUTTONS
- run/stop: this is really a toggle!
- initialize: returns the velocity distribution to Maxwellian, the spacial distribution to a localized Gaussian, and clears the graphs. Key equivalent is the i-key.
- presets: Takes you to a tear-off menu with which you may select the presets. For more details, see the preset item in the miscellaneous help file.
- configure:
- number of electrons: the number of electrons in the ensemble.(Restricted to positive integer.)
- graph update increment: the number of computer cycles between subsequent rewrites of the display: one of two controlling factors in the animation speed. (Restricted to positive integer.)
- revert: updates the listed configure parameters to the current values (which may have been changed by a preset command).
- close: closes the configure window.
- help: Opens the help system which you have already found!
- quit: Terminates "drude".
DISPLAYS
- left side: a square field, 8 micrometers on a side, displaying electron positions; the coordinates of the cursor are given below the display. The large red dot is the origin; the large green dot is the average position of the electrons.
- right side: a square field, 8*10^5 m/s on a side, displaying electron velocities; the coordinates of the cursor are given below the display. The red bar at the top gives a qualitative indication of the magnitude, direction and time dependence of the electric field. The large red dot is the origin; the large green dot is the average velocity of the electrons.
READOUTS
- time: a clock, in the left-hand display, gives the elapsed simulation time, since the previous initialization, in picoseconds.
- cursor coordinates: below each display field, the coordinates of the cursor, when in the field, are given. Units are 10^-6 m for the position field, and 10^4 m/s for the velocity field.