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/* Copyright 2019 Luca Fedeli
*
* This file is part of WarpX.
*
* License: BSD-3-Clause-LBNL
*/
#include "Laser/LaserProfiles.H"
#include "Utils/WarpXConst.H"
#include "Utils/WarpXUtil.H"
#include "Utils/WarpX_Complex.H"
#include <AMReX_Extension.H>
#include <AMReX_GpuLaunch.H>
#include <AMReX_GpuQualifiers.H>
#include <AMReX_REAL.H>
#include <cmath>
using namespace amrex;
void
WarpXLaserProfiles::HarrisLaserProfile::init (
const amrex::ParmParse& ppl,
const amrex::ParmParse& /* ppc */,
CommonLaserParameters params)
{
// Parse the properties of the Harris profile
getWithParser(ppl, "profile_waist", m_params.waist);
getWithParser(ppl, "profile_duration", m_params.duration);
getWithParser(ppl, "profile_focal_distance", m_params.focal_distance);
//Copy common params
m_common_params = params;
}
/* \brief compute field amplitude for a Harris laser function, at particles' position
*
* Both Xp and Yp are given in laser plane coordinate.
* For each particle with position Xp and Yp, this routine computes the
* amplitude of the laser electric field, stored in array amplitude.
*
* \param np: number of laser particles
* \param Xp: pointer to first component of positions of laser particles
* \param Yp: pointer to second component of positions of laser particles
* \param t: Current physical time
* \param amplitude: pointer to array of field amplitude.
*/
void
WarpXLaserProfiles::HarrisLaserProfile::fill_amplitude (
const int np, Real const * AMREX_RESTRICT const Xp, Real const * AMREX_RESTRICT const Yp,
Real t, Real * AMREX_RESTRICT const amplitude) const
{
// This function uses the Harris function as the temporal profile of the pulse
const Real omega0 =
2._rt*MathConst::pi*PhysConst::c/m_common_params.wavelength;
const Real zR = MathConst::pi * m_params.waist*m_params.waist
/ m_common_params.wavelength;
const Real wz = m_params.waist *
std::sqrt(1._rt + m_params.focal_distance*m_params.focal_distance/(zR*zR));
const Real inv_wz_2 = 1._rt/(wz*wz);
Real inv_Rz;
if (m_params.focal_distance == 0.){
inv_Rz = 0.;
} else {
inv_Rz = -m_params.focal_distance /
( m_params.focal_distance*m_params.focal_distance + zR*zR );
}
const Real arg_env = 2._rt*MathConst::pi*t/m_params.duration;
// time envelope is given by the Harris function
Real time_envelope = 0.;
constexpr auto norm = 1._rt/32._rt;
constexpr auto c_0 = 10._rt;
constexpr auto c_1 = -15._rt;
constexpr auto c_2 = 6._rt;
constexpr auto c_3 = -1._rt;
constexpr auto a_1 = 1._rt;
constexpr auto a_2 = 2._rt;
constexpr auto a_3 = 3._rt;
if (t < m_params.duration)
time_envelope = norm * (c_0 +
c_1*std::cos(a_1*arg_env) +
c_2*std::cos(a_2*arg_env) +
c_3*std::cos(a_3*arg_env));
// Copy member variables to tmp copies for GPU runs.
const auto tmp_e_max = m_common_params.e_max;
// Loop through the macroparticle to calculate the proper amplitude
amrex::ParallelFor(
np,
[=] AMREX_GPU_DEVICE (int i) {
const Real space_envelope =
std::exp(- ( Xp[i]*Xp[i] + Yp[i]*Yp[i] ) * inv_wz_2);
const Real arg_osc = omega0*t - omega0/PhysConst::c*
(Xp[i]*Xp[i] + Yp[i]*Yp[i]) * inv_Rz / 2._rt;
const Real oscillations = std::cos(arg_osc);
amplitude[i] = tmp_e_max * time_envelope *
space_envelope * oscillations;
}
);
}
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