loasis3.inp{Here we make an initial attempt to model the effects of small-scalevariations in the neutral gas density, and how it might be impactingthe laser plasma experiments in the l'OASIS laboratory of Wim Leemanset al. at LBNL.Pulse with transverse Gaussian profile and y polarization is launched fromthe left boundary. Cartesian geometry, no plasma initially, background of neutral H gas.This is derived from loasis2.inp -- here we turn off the moving windowand run the laser pulse through a model of a gas bubble.}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// **********************************************************************// 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//   10^14 to 10^15 W/cm^2//  peakLaserIntensity = 1e+16  // 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 = 10  dy = dx * gridSizeRatio  Lx = Nx * dx  Ly = Ny * dy  d = 1. / sqrt( 1./(dx*dx) + 1./(dy*dy) )  timeStep = 0.7 * 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 = 3.0 * 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  c1 = Lx / 2.  c2 = Ly / 2.  r1  =  4.e-6  r2  = 20.e-6  numZeroCells = 2  numRampCells = 2  zeroEnd = (numZeroCells + .5) * dx  rampEnd = (numZeroCells + numRampCells + .5) * 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}Control{  dt = timeStep}Species{  name = electrons  m = electronMass   q = electronCharge   particleLimit = 2.5e+05 // prevents out-of-control growth in # of ptcls}Species{  name = ions  m = hydrogenMass  q = ionCharge// -- you can't subcycle the ions, because they are moved by the high-frequency//    oscillations of the laser pulse//  subcycle = 20  particleLimit = 1.0e+05 // prevents out-of-control growth in # of ptcls}// Specify the Monte Carlo collision parameters for background gasMCC{  gas                         = H  pressure                    = gasPressureTorr  temperature                 = gasTempEV  // The first term keeps macro-particles away from the laser-emitting boundary and ramps  // up the density.  The ramp may not be necessary.  //  // The second term then adds or subtracts gas density from an elliptical region.  This is  // an attempt to model spherical bubbles of higher or lower density.  //  analyticF = gasDensityMKS * ( step(x1-zeroEnd) - step(1.-(x1-c1)*(x1-c1)/(r1*r1)-(x2-c2)*(x2-c2)/(r2*r2)) )  eSpecies                    = electrons  iSpecies                    = ions  // 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  // 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 = 1 // 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}}