impactx::particles::spacecharge Namespace Reference

Functions
void	ForceFromSelfFields (std::unordered_map< int, std::unordered_map< std::string, amrex::MultiFab > > &space_charge_field, std::unordered_map< int, amrex::MultiFab > const &phi, amrex::Vector< amrex::Geometry > const &geom)
void	GatherAndPush (ImpactXParticleContainer &pc, std::unordered_map< int, std::unordered_map< std::string, amrex::MultiFab > > const &space_charge_field, const amrex::Vector< amrex::Geometry > &geom, amrex::ParticleReal const slice_ds)
AMREX_GPU_DEVICE void	efldgauss (int nint, amrex::ParticleReal const xin, amrex::ParticleReal const yin, amrex::ParticleReal const zin, amrex::ParticleReal const sigx, amrex::ParticleReal const sigy, amrex::ParticleReal const sigz, amrex::ParticleReal const gamma, amrex::ParticleReal &pintex, amrex::ParticleReal &pintey, amrex::ParticleReal &pintez)
void	Gauss3dPush (ImpactXParticleContainer &pc, amrex::ParticleReal const slice_ds)
void	HandleSpacecharge (std::unique_ptr< initialization::AmrCoreData > &amr_data, std::function< void()> ResizeMesh, amrex::Real slice_ds)
void	PoissonSolve (ImpactXParticleContainer const &pc, std::unordered_map< int, amrex::MultiFab > &rho, std::unordered_map< int, amrex::MultiFab > &phi, amrex::Vector< amrex::IntVect > rel_ref_ratio)

Function Documentation

efldgauss()

AMREX_GPU_DEVICE void impactx::particles::spacecharge::efldgauss	(	int	nint,
		amrex::ParticleReal const	xin,
		amrex::ParticleReal const	yin,
		amrex::ParticleReal const	zin,
		amrex::ParticleReal const	sigx,
		amrex::ParticleReal const	sigy,
		amrex::ParticleReal const	sigz,
		amrex::ParticleReal const	gamma,
		amrex::ParticleReal &	pintex,
		amrex::ParticleReal &	pintey,
		amrex::ParticleReal &	pintez )

Compute space-charge fields from a 3D Gaussian distribution.

Compute integrals Eqs 45-47 used in the space-charge fields from a 3D Gaussian distribution. "A two-and-a-half dimensional symplectic space-charge solver", LBNL Report Number: LBNL-2001674, 2025. Input particle locations (x,y,z) and RMS sizes (sigx,sigy,sigz) and return the integrals for SC fields.

Todo

This function can be vectorized with AMREX_SIMD for better CPU performance.

ForceFromSelfFields()

void impactx::particles::spacecharge::ForceFromSelfFields	(	std::unordered_map< int, std::unordered_map< std::string, amrex::MultiFab > > &	space_charge_field,
		std::unordered_map< int, amrex::MultiFab > const &	phi,
		const amrex::Vector< amrex::Geometry > &	geom )

Calculate the space charge force field from the electric potential

This resets the values in scf_<component> to zero and then calculates the space charge force field.

Parameters

[in,out]	space_charge_field	space charge force component in x,y,z per level
[in]	phi	scalar potential per level
[in]	geom	geometry object

GatherAndPush()

void impactx::particles::spacecharge::GatherAndPush	(	ImpactXParticleContainer &	pc,
		std::unordered_map< int, std::unordered_map< std::string, amrex::MultiFab > > const &	space_charge_field,
		const amrex::Vector< amrex::Geometry > &	geom,
		amrex::ParticleReal	slice_ds )

Gather force fields and push particles in x,y,z

This gathers the space charge field with respect to particle position and shape. The momentum of all particles is then pushed using a common time step given by the reference particle speed and ds slice. The position push is done in the lattice elements and not here.

Parameters

[in,out]	pc	container of the particles that deposited rho
[in]	space_charge_field	space charge force component in x,y,z per level
[in]	geom	geometry object
[in]	slice_ds	segment length in meters

Gauss3dPush()

void impactx::particles::spacecharge::Gauss3dPush	(	ImpactXParticleContainer &	pc,
		amrex::ParticleReal	slice_ds )

Apply a Space-Charge Kick according to a 3D Gaussian Distribution

This calculates the space charge fields from a 3D Gaussian distribution with respect to particle position from the following paper: J. Qiang et al., "Two-and-a-half dimensional symplectic space-charge solver", LBNL Report Number: LBNL-2001674 (2025). The momentum of all particles is then pushed using a common time step given by the reference particle speed and ds slice. The position push is done in the lattice elements and not here.

Parameters

[in,out]	pc	container of the particles that deposited rho
[in]	slice_ds	segment length in meters

HandleSpacecharge()

void impactx::particles::spacecharge::HandleSpacecharge	(	std::unique_ptr< initialization::AmrCoreData > &	amr_data,
		std::function< void()>	ResizeMesh,
		amrex::Real	slice_ds )

Function to handle space charge including charge deposition, Poisson solve, field calculation, interpolation, and particle push.

Parameters

[in,out]	amr_data	AMR data like particle container and fields
[in]	ResizeMesh	function to call to resize the mesh
[in]	slice_ds	slice spacing along s

PoissonSolve()

void impactx::particles::spacecharge::PoissonSolve	(	ImpactXParticleContainer const &	pc,
		std::unordered_map< int, amrex::MultiFab > &	rho,
		std::unordered_map< int, amrex::MultiFab > &	phi,
		amrex::Vector< amrex::IntVect >	rel_ref_ratio )

Calculate the electric potential from charge density

This resets the values in phi to zero and then calculates the space charge potential phi.

Parameters

[in]	pc	container of the particles that deposited rho
[in]	rho	charge per level
[in,out]	phi	scalar potential per level
[in]	rel_ref_ratio	mesh refinement ratio between levels