8 #ifndef WARPX_PARTICLES_PUSHER_UPDATEMOMENTUM_VAY_H_
9 #define WARPX_PARTICLES_PUSHER_UPDATEMOMENTUM_VAY_H_
21 amrex::ParticleReal& ux, amrex::ParticleReal& uy, amrex::ParticleReal& uz,
22 const amrex::ParticleReal Ex,
const amrex::ParticleReal Ey,
const amrex::ParticleReal Ez,
23 const amrex::ParticleReal Bx,
const amrex::ParticleReal By,
const amrex::ParticleReal Bz,
24 const amrex::ParticleReal q,
const amrex::ParticleReal m,
const amrex::Real
dt )
26 using namespace amrex::literals;
29 const amrex::ParticleReal econst = q*
dt/m;
30 const amrex::ParticleReal bconst = 0.5_prt*q*
dt/m;
31 constexpr amrex::ParticleReal invclight = 1._prt/
PhysConst::c;
34 const amrex::ParticleReal inv_gamma = 1._prt/std::sqrt(1._prt + (ux*ux + uy*uy + uz*uz)*invclightsq);
36 const amrex::ParticleReal taux = bconst*Bx;
37 const amrex::ParticleReal tauy = bconst*By;
38 const amrex::ParticleReal tauz = bconst*Bz;
39 const amrex::ParticleReal tausq = taux*taux+tauy*tauy+tauz*tauz;
41 const amrex::ParticleReal uxpr = ux + econst*Ex + (uy*tauz-uz*tauy)*inv_gamma;
42 const amrex::ParticleReal uypr = uy + econst*Ey + (uz*taux-ux*tauz)*inv_gamma;
43 const amrex::ParticleReal uzpr = uz + econst*Ez + (ux*tauy-uy*taux)*inv_gamma;
44 const amrex::ParticleReal gprsq = (1._prt + (uxpr*uxpr + uypr*uypr + uzpr*uzpr)*invclightsq);
46 const amrex::ParticleReal ust = (uxpr*taux + uypr*tauy + uzpr*tauz)*invclight;
48 const amrex::ParticleReal sigma = gprsq-tausq;
49 const amrex::ParticleReal gisq = 2._prt/(sigma + std::sqrt(sigma*sigma + 4._prt*(tausq + ust*ust)) );
51 const amrex::ParticleReal bg = bconst*std::sqrt(gisq);
52 const amrex::ParticleReal tx = bg*Bx;
53 const amrex::ParticleReal ty = bg*By;
54 const amrex::ParticleReal tz = bg*Bz;
55 const amrex::ParticleReal s = 1._prt/(1._prt+tausq*gisq);
57 const amrex::ParticleReal tu = tx*uxpr + ty*uypr + tz*uzpr;
59 ux = s*(uxpr+tx*tu+uypr*tz-uzpr*ty);
60 uy = s*(uypr+ty*tu+uzpr*tx-uxpr*tz);
61 uz = s*(uzpr+tz*tu+uxpr*ty-uypr*tx);
#define AMREX_GPU_HOST_DEVICE
AMREX_GPU_HOST_DEVICE AMREX_INLINE void UpdateMomentumVay(amrex::ParticleReal &ux, amrex::ParticleReal &uy, amrex::ParticleReal &uz, const amrex::ParticleReal Ex, const amrex::ParticleReal Ey, const amrex::ParticleReal Ez, const amrex::ParticleReal Bx, const amrex::ParticleReal By, const amrex::ParticleReal Bz, const amrex::ParticleReal q, const amrex::ParticleReal m, const amrex::Real dt)
Push the particle's positions over one timestep, given the value of its momenta ux,...
Definition: UpdateMomentumVay.H:20
static constexpr auto c
vacuum speed of light [m/s]
Definition: constant.H:44
float dt
Definition: stencil.py:442