impactx::particles::spacecharge Namespace Reference

Functions
amrex::Gpu::DeviceVector< amrex::Real >	Deposit1D (ImpactXParticleContainer &pc, amrex::Real bin_min, amrex::Real bin_max, int num_bins)
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, std::unordered_map< int, amrex::MultiFab > const &space_charge_potential, const amrex::Vector< amrex::Geometry > &geom, amrex::ParticleReal const slice_ds)
AMREX_GPU_DEVICE void	potInt (amrex::ParticleReal delta, int nint, amrex::ParticleReal xin, amrex::ParticleReal yin, amrex::ParticleReal sigx, amrex::ParticleReal sigy, amrex::ParticleReal &pintex, amrex::ParticleReal &pintey, amrex::ParticleReal &pintez)
void	Gauss2p5dPush (ImpactXParticleContainer &pc, 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

Deposit1D()

amrex::Gpu::DeviceVector< amrex::Real > impactx::particles::spacecharge::Deposit1D	(	ImpactXParticleContainer &	pc,
		amrex::Real	bin_min,
		amrex::Real	bin_max,
		int	num_bins )

Deposit charge using longitudinal binning for the calculation of space charge

This function performs particle binning for particles in the beam along the longitudinal direction, for the purposes of computing space charge in so-called 2.5D models.

Parameters

[in]	pc	container of the particles that deposited rho
[in]	bin_min	location of lower endpoint for binning
[in]	bin_max	location of upper endpoint for binning
[in]	num_bins	number of longitudinal bins

Returns

beam_profile deposited charge density

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,
		std::unordered_map< int, amrex::MultiFab > const &	space_charge_potential,
		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]	space_charge_potential	space charge potential in x,y,z per level
[in]	geom	geometry object
[in]	slice_ds	segment length in meters

Gauss2p5dPush()

void impactx::particles::spacecharge::Gauss2p5dPush	(	ImpactXParticleContainer &	pc,
		amrex::ParticleReal	slice_ds )

Calculate the 2.5D Space Charge fields for a transverse Gaussian Distribution

This calculates the space charge fields from a transverse Gaussian distribution with respect to particle position from the following paper. "Two-and-a-half dimensional symplectic space-charge solver" 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

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

potInt()

AMREX_GPU_DEVICE void impactx::particles::spacecharge::potInt	(	amrex::ParticleReal	delta,
		int	nint,
		amrex::ParticleReal	xin,
		amrex::ParticleReal	yin,
		amrex::ParticleReal	sigx,
		amrex::ParticleReal	sigy,
		amrex::ParticleReal &	pintex,
		amrex::ParticleReal &	pintey,
		amrex::ParticleReal &	pintez )

Calculate the Integrals for Space Charge Fields

Compute integrals Eqs 25, 31,32 used in the space-charge fields from a 2D transverse Gaussian distribution (including 2A in Eq. 25). Input particle locations (x,y) and RMS sizes (sigx,sigy) and return the integrals for SC fields.