PlasmaMLPALLASMagneticField.cc File Reference

Implementation of the PlasmaMLPALLASMagneticField class and related fit functions. More...

#include "PlasmaMLPALLASMagneticField.hh"
#include "TMath.h"
#include "TF1.h"

Include dependency graph for PlasmaMLPALLASMagneticField.cc:

Functions
G4double	fitFunction (G4double *x, G4double *par)
	Fit function for magnetic field profile.
G4double	symmetrizedFunctionY (G4double *x, G4double *par)
	Symmetrized fit function along Y axis.
G4double	symmetrizedFunctionS (G4double *x, G4double *par)
	Symmetrized fit function along S axis.

Detailed Description

Implementation of the PlasmaMLPALLASMagneticField class and related fit functions.

This file implements the PlasmaMLPALLASMagneticField class, providing magnetic field definitions for the PALLAS PlasmaMLP simulation, including:

• Dipole field (constant or mapped)
• Quadrupole field contributions
• Fit functions for modeling magnetic field profiles along Y and S axes using combinations of error functions and Gaussians.

The class provides methods to:

• Compute the magnetic field at any point in space.
• Set or retrieve quadrupole gradients, lengths, and drift distances.
• Enable or disable mapped-field mode.
• Configure a constant dipole field when mapped-field mode is disabled.

Fit functions:

• fitFunction() : Computes a combination of an error function step and a Gaussian.
• symmetrizedFunctionY(): Reflects fitFunction about x0 = 0 for Y-axis symmetry.
• symmetrizedFunctionS(): Reflects fitFunction about x0 = 3.4495 for S-axis symmetry.

Magnetic field computation:

• Uses dipole field or mapped-field mode depending on StatusMapBField.
• Adds quadrupole contributions according to the configured gradients, lengths, and drifts.

This implementation is compatible with Geant4 and CLHEP units.

Author

Arnaud HUBER huber.nosp@m.@lp2.nosp@m.ib.in.nosp@m.2p3..nosp@m.fr

Alexei SYTOV sytov.nosp@m.@inf.nosp@m.n.it

Date

2025

Copyright

PALLAS Project - GEANT4 Collaboration

Function Documentation

fitFunction()

G4double fitFunction	(	G4double *	x,
		G4double *	par
	)

Fit function for magnetic field profile.

Fit function for magnetic field profiles.

Computes a combination of an error function step and a Gaussian depending on position.

Parameters

x	Pointer to position array
par	Pointer to parameter array

Returns

Calculated magnetic field value

symmetrizedFunctionS()

G4double symmetrizedFunctionS	(	G4double *	x,
		G4double *	par
	)

Symmetrized fit function along S axis.

Symmetrized fit function along the S-axis.

Reflects the function about x0 = 3.4495 to enforce symmetry.

Parameters

x	Pointer to position array
par	Pointer to parameter array

Returns

Magnetic field value

symmetrizedFunctionY()

G4double symmetrizedFunctionY	(	G4double *	x,
		G4double *	par
	)

Symmetrized fit function along Y axis.

Symmetrized fit function along the Y-axis.

Reflects the function about x0 = 0 to enforce symmetry.

Parameters

x	Pointer to position array
par	Pointer to parameter array

Returns

Magnetic field value