laser_solid.inp

pic 模拟程序！面向对象

laser_solid.inp
{

Here we make an initial attempt to model acceleration
of ions from the backside of a thin film.

Pulse with transverse half-sine profile and z polarization 
is launched from the left boundary. 

We use Cartesian (2-D slab) geometry.

The bulk of the thin film is a solid-density H gas, but the
generated H ions are given a large mass, so that they don't
move.  This is not very realistic, but we are just trying
to see if we can capture the basic phenomena. 

The back side of the film has an even thinner layer of (mobile)
F7+ ions and 7 times as many (preionized) electrons.  Again,
this is not realistic, but recent experimental work indicates
that F7+ is effectively accelerated to high-energy from a thin
CaF2 coating on the back of an Al film.
}

Variables
{
// General numerical parameters
  PI = 3.14159

// **********************************************************************
// General physical parameters
// **********************************************************************
  electronMass = 9.1094e-31 
  electronCharge = -1.6022e-19
  permit = 8.8542e-12 
  speedLight = 2.9979e8
  speedLight2 = speedLight*speedLight 
  electronCharge2 = electronCharge*electronCharge 
  qOverM = electronCharge/electronMass

  ionCharge = -electronCharge
  unitMassMKS = electronMass / 5.48579903e-04
  hydrogenMassNum = 1.00797
  hydrogenMass = unitMassMKS * hydrogenMassNum
  fluorineMassNum = 18.9984
  fluorineMass = unitMassMKS * fluorineMassNum
  fluorineCharge = 7. * ionCharge

// **********************************************************************
// Plasma parameters
// **********************************************************************
//   Here, we specify a zero plasma density, because we launch the laser
//   pulse into a vacuum region.  Down below, we define the parameters
//   used for loading the initial electron plasma into the simulation.
  elecPlasmaDensity =  0.0
  elecPlasmaFreq = sqrt(electronCharge*qOverM*elecPlasmaDensity/permit)
 
// **********************************************************************
// Laser pulse parameters - z polarization
// **********************************************************************
//   We are modeling a laser pulse with wavelength of 0.8 micron and
//   FHWM pulse length of ~50 fs, and a peak intensity of ~10^19 W/cm^2
//
//   We are using a half sine function for the longitudinal shape of
//   the pulse and Gaussians for the transverse directions with the
//   same standard deviations sigma_r, same as waistSize below. 
//
//   The energy of the pulse is ~500 mJ.
//
//   In terms of the energy of the pulse [J], called here "energyOfPulse",
//   the FHWM pulse length [s] "pulseLengthFWHM" and the transverse 
//   width "waistSize" [m], the peak laser intensity is given by: 
//
//   Ipeak = (2*energyOfPulse)/(1.5*pulseLengthFWHM*PI*waistSize^2)
//         ~ 4e23 W/m^2
//         ~ 4e19 W/cm^2
//
  energyOfPulse =   300.0e-03     // [J]
  pulseLengthFWHM =  30.0e-15     // [s]      
  waistSize =         3.0e-06     // [m] 
  laserWavelength =   0.8e-06     // [m]
  laserFrequency = 2.*PI*speedLight/laserWavelength
  peakElectricField = sqrt(8.*energyOfPulse/(1.5*permit*speedLight*pulseLengthFWHM*PI*waistSize*waistSize))

// **********************************************************************
// Grid parameters
// **********************************************************************
// We must resolve the laser wavelength
  numGridsPerWavelength = 16
  dx = laserWavelength / numGridsPerWavelength
  Nx = 32 * numGridsPerWavelength
  Lx = Nx * dx

  gridSizeRatio = 1
  dy = dx * gridSizeRatio
  Ny = 32 * numGridsPerWavelength / gridSizeRatio
  Ly = Ny * dy

  d = 1. / sqrt( 1./(dx*dx) + 1./(dy*dy) )
  timeStep = 0.99 * d / speedLight

// **********************************************************************
// Plasma parameters
// **********************************************************************
// An electron density of 1.736e+27 m^-3 leads to a plasma wavelength
//   of 0.8 microns.
//  plasmaDensityMKS = 1.736e+27
  plasmaDensityMKS = 7.0e+27

  numZeroCells    =  13.0 * numGridsPerWavelength
  numSlabCells_H  =  18.0 * numGridsPerWavelength
  numSlabCells_F  =   0.5 * numGridsPerWavelength
  
  numPlasmaCellsX = numSlabCells_H + numSlabCells_F
  numPlasmaCellsY = Ny
  numPlasmaCells  = numPlasmaCellsX * numPlasmaCellsY

  totalNumElectrons  = plasmaDensityMKS * dx * dy * 1.0 * numPlasmaCellsY * numPlasmaCellsX
  numPtclsPerCell    = 8
  totalNumMacroPtcls = numPtclsPerCell * numPlasmaCells
  np2cRatio          = totalNumElectrons / totalNumMacroPtcls

// This is the desired delay time before the moving window algorithm activates.
  movingWindowDelay = 1.8 * numZeroCells * dx / speedLight

// **********************************************************************
// Define gas density, pressure and other MCC parameters
// **********************************************************************
  gasTempEV       = 1.0e-06  // make gas cold (cannot set temperature to zero)
  gasDensityMKS   = plasmaDensityMKS
  gasPressureTorr = 1.20e-21 * gasDensityMKS * gasTempEV

// **********************************************************************
// More laser parameters:
// **********************************************************************
// We model the laser pulse envelope as a Gaussian (nPulseShape=1).
// or a half sine shape (nPulseShape=2)
  nPulseShape = 2
  pulseLength  = 1.5 * pulseLengthFWHM * speedLight

// Here we specify Rayleigh length, etc.
// These parameters are for a pulse with z-polarization.
  angFreq = laserFrequency
  angFreq2 = angFreq * angFreq
  waveVector = sqrt( (angFreq2-elecPlasmaFreq*elecPlasmaFreq) / speedLight2 )
  rayleighLength = waistSize * waistSize * waveVector / 2.
  waistLocation = numZeroCells * dx
}

Region
{
Grid
{
  J = Nx 
  x1s = 0.0
  x1f = Lx
  n1 = 1.0 
  K = Ny 
  x2s = 0.0
  x2f = Ly 
  n2 = 1.0
  Geometry = 1
  PeriodicFlagX2 = 1	
}

Control
{
  dt = timeStep

// Turn off the initial Poisson solve
  initPoissonSolve=0

// Turn on the moving window algorithm.
  movingWindow = 1
  shiftDelayTime = movingWindowDelay
}

// Define the electrons
Species
{
  name = electrons
  m = electronMass 
  q = electronCharge 
  collisionModel = 1
}

// Define the F7+ macro-particles
Species
{
  name = fluorineP7
  m = fluorineMass 
  q = fluorineCharge 
}

// Define the H+ species (no macro-particles will be generated).
Species
{
  name = heavyProtons
  m = 1e6*hydrogenMass
  q = ionCharge
}

// Load the plasma electrons over a thin rectangular region within
//   the grid, covering only the F7+ film.
Load
{
  speciesName = electrons
//  density = plasmaDensityMKS
  analyticF = plasmaDensityMKS

  x1MinMKS = (numZeroCells + numSlabCells_H) * dx
  x1MaxMKS = (numZeroCells + numSlabCells_H + numSlabCells_F) * dx
  x2MinMKS = 0.
  x2MaxMKS = Ly

  np2c = np2cRatio

// Specify loading that is more uniform than random
  LoadMethodFlag = 1
}


// Load the Fluorine 7+ ions over the F slab.
Load
{
  speciesName = fluorineP7
//  density = plasmaDensityMKS / 7.
  analyticF = plasmaDensityMKS / 7.

  x1MinMKS = (numZeroCells + numSlabCells_H) * dx
  x1MaxMKS = (numZeroCells + numSlabCells_H + numSlabCells_F) * dx
  x2MinMKS = 0.
  x2MaxMKS = Ly

  np2c = np2cRatio / 21.

// Specify loading that is more uniform than random
  LoadMethodFlag = 1
}


// Specify the Monte Carlo collision parameters for the background gas
// We use the hydrogen cross-sections for impact ionization and elastic scattering.
// We also use tunneling ionization rate for hydrogen.
MCC
{
  gas         = H
  pressure    = gasPressureTorr
  temperature = gasTempEV

  x1MinMKS = numZeroCells * dx
  x1MaxMKS = 
  x2MinMKS = 0.
  x2MaxMKS = Ly

  analyticF = gasDensityMKS * step( x1 - numZeroCells*dx ) * step( (numZeroCells+numSlabCells_H)*dx - x1 )

  eSpecies                = electrons
  iSpecies                = heavyProtons

  // turn on electron/ion collisions, including impact ionization
  collisionFlag = 1
  relativisticMCC = 1

  // turn on tunneling ionization in linearly polarized alternating field
  tunnelingIonizationFlag = 1

 // specify static field / circular polarization
  ETIPolarizationFlag     = 1

  // specify the characteristic oscillation frequency of the electric field
  // -- here we fudge the real frequency with a small factor --
  EfieldFrequency =  laserFrequency

  // fix the number of macro particles to be created in each cell
  TI_numMacroParticlesPerCell = 20
}

// Launch the laser pulse
// This subsequently applies conducting boundary conditions along the left
//    boundary.  It would be good if this could become an ExitPort...
PortGauss
{
  j1 = 0 
  j2 = 0 
  k1 = 0 
  k2 = Ny 
  normal = 1

  A = 0
  C = 1.0 

// Wave (0)
  pulShp_p0 = nPulseShape
  tdelay_p0 = 0.0 
  pulLeng_p0 = pulseLength
  chirp_p0 = 0.0
  spotSize_p0 = waistSize
  waveLeng_p0 = laserWavelength
  focus_p0 = waistLocation
  amp_p0 = 0.0

// Wave (1)
  pulShp_p1 = nPulseShape
  tdelay_p1 = 0.0
  pulLeng_p1 = pulseLength
  chirp_p1 = 0.0
  spotSize_p1 = waistSize
  waveLeng_p1 = laserWavelength
  focus_p1 = waistLocation
  amp_p1 = peakElectricField

  EFFlag = 0 
  name = PortGauss
}

// Top boundary
//Conductor
//{
//  j1 = 0
//  j2 = Nx
//  k1 = Ny 
//  k2 = Ny 
//  normal = -1
//}

// Bottom boundary
//Conductor
//{
//  j1 = 0
//  j2 = Nx
//  k1 = 0
//  k2 = 0
//  normal = 1
//}

// Right boundary
Conductor
{
  j1 = Nx
  j2 = Nx
  k1 = 0
  k2 = Ny
  normal = -1
}

}