loasisHe.inp
{

Here we make an initial attempt to model some aspects of
the laser plasma experiments in the l'OASIS laboratory of
Wim Leemans et al. at LBNL.

Pulse with transverse Gaussian profile and y polarization is launched from
the left boundary. 

Cartesian geometry, no plasma initially, background of neutral H gas.

This is derived from loasis2.inp -- here we replace H with He and
further increase the laser intenstiy by an order of magnitude.
}

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
  HeMassNum = 4.0026
  HeMass = unitMassMKS * HeMassNum

// **********************************************************************
// Plasma parameters
// **********************************************************************
//   Here, we have zero initial plasma density.
  elecPlasmaDensity =  0.0 
  elecPlasmaFreq = sqrt(electronCharge*qOverM*elecPlasmaDensity/permit)
 
// **********************************************************************
// Laser pulse parameters - y polarization
// **********************************************************************
//   We are modeling a laser pulse with wavelength of 0.8 micron and
//   FHWM pulse length of 50 fs to 200 fs, and a peak intensity of
//   10^16 to 10^18 W/cm^2
//
  peakLaserIntensity = 1e+17  // W/cm^2
  pulseLengthFWHM = 50.e-15
  laserWavelength = 0.8e-06
  laserFrequency = 2.*PI*speedLight/laserWavelength
  // We must convert the intensity to MKS units
  peakLaserIntensityMKS = peakLaserIntensity * 1.0e+04
  peakElectricField = sqrt(2.*peakLaserIntensityMKS/speedLight/permit)

// **********************************************************************
// Grid parameters
// **********************************************************************
// We must resolve the laser wavelength
  Nx = 512
  Ny = 256
  numGridsPerWavelength = 16
  dx = laserWavelength / numGridsPerWavelength
  gridSizeRatio = 16
  dy = dx * gridSizeRatio
  Lx = Nx * dx
  Ly = Ny * dy

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

// **********************************************************************
// More laser parameters:
// **********************************************************************
// We model the laser pulse envelope as a Gaussian (nPulseShape=1).
  nPulseShape = 1
  pulseLength  = pulseLengthFWHM * speedLight

// Here we specify the waist size, Rayleigh length, etc.
// These parameters are for a pulse with y-polarization.
  waistSize = 6.0e-06 
  angFreq = laserFrequency
  angFreq2 = angFreq * angFreq
  waveVector = sqrt( (angFreq2-elecPlasmaFreq*elecPlasmaFreq) / speedLight2 )
  rayleighLength = waistSize * waistSize * waveVector / 2.
  waistLocation = 0.25 * rayleighLength

// **********************************************************************
// Define gas density, pressure and other MCC parameters
// **********************************************************************
  gasTempEV       = 1.0e-06  // make gas cold (cannot set temperature to zero)
  gasDensityMKS   = 2.e25
  gasPressureTorr = 1.20e-21 * gasDensityMKS * gasTempEV

  numFlatCells = 4
  numRampCells = 4
  numZeroCells = Nx - numFlatCells - numRampCells
  zeroEnd = (numZeroCells + .5) * dx
  rampEnd = (numZeroCells + numRampCells + .5) * dx

// we need to turn off the gas jet after two Rayleigh lengths
  NGDSwitchOffTime = 2. * rayleighLength / speedLight

// This is the desired delay time before the moving window algorithm activates.
  movingWindowDelay = (Nx-15) * dx / speedLight
}

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

Control
{
  dt = timeStep

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

// Turn off the gas jet after some time
  gasOffTime = NGDSwitchOffTime
}

Species
{
  name = electrons
  m = electronMass 
  q = electronCharge 
  particleLimit = 2.5e+05 // prevents out-of-control growth in # of ptcls
}

Species
{
  name = HePlus
  m = HeMass
  q = ionCharge
  particleLimit = 1.0e+05 // prevents out-of-control growth in # of ptcls
}

Species
{
  name = HePlusPlus
  m = HeMass
  q = 2*ionCharge
  particleLimit = 1.0e+05 // prevents out-of-control growth in # of ptcls
}

// Specify the Monte Carlo collision parameters for background gas
MCC
{
  gas                         = He
  pressure                    = gasPressureTorr
  temperature                 = gasTempEV
  analyticF = gasDensityMKS * step(x1-zeroEnd) * ( ramp( (x1-zeroEnd)/(rampEnd-zeroEnd) ) * step(rampEnd-x1) + step(x1-rampEnd) )

  eSpecies                = electrons
  iSpecies                = HePlus
  iSpeciesPlusPlus        = HePlusPlus

  // turn OFF electron/ion collisions, including impact ionization
  collisionFlag = 0

  // 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 = 8
}
//Diagnostic
//{
//	j1 = 0
//	j2 = Nx
//	k1 = 0
//	k2 = Ny
//	VarName = WaveDirDiagnostic
//       polarizationEB = EzBy
//      psd1dFlag = 0 // calculate the 1d power spectral density
//     windowName = Blackman
//	title = Wave Energy
//	x1_Label = x
//	x2_Label = y
//	x3_Label = Wave Energy
//}
PortGauss
{
  j1 = 0 
  k1 = 0 
  j2 = 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
}


ExitPort
{
  j1 = 0
  k1 = Ny 
  j2 = Nx 
  k2 = Ny 
  normal = -1
  EFFlag = 0 
  name = ExitPort
  C = 0
  A = 0
}

ExitPort
{
  j1 = 0
  k1 = 0 
  j2 = Nx 
  k2 = 0 
  normal = 1
  EFFlag = 0 
  name = ExitPort
  C = 0
  A = 0
}

Conductor
{
  j1 = Nx
  k1 = 0
  j2 = Nx
  k2 = Ny
  normal = -1
  EFFlag = 0 
  name = ExitPort
  C = 0
  A = 0
}

}