- Direct Known Subclasses:
- Cartesian3DMagneticFieldMap, ConstantMagneticField, SplineFit1DMagneticFieldMap
public abstract class AbstractMagneticField
extends Object
AbstractMagneticField is a general magnetic field class which returns values
interesting for tracking code. A magnetic field will generally have an
internal representation optimized for speed which will need to be updated
whenever the field is moved or rescaled. Important methods are:
SpacePointVector field( SpacePoint p); SpacePointVector field( SpacePoint p,
SpacePointTensor g); return the field at p and calculates the gradient
tensor. The returned field and the gradient are in the form of a value at the
point p.
Note regarding gradient tensor:
The gradient tensor is a matrix of covariant derivates, which can be defined,
or its components extracted, in any standard coordinate system (namely,
Cartesian, cylindrical, spherical).
In Cartesian coordinates, covariant derivatives is the same as ordinary
partial derivatives:
Bi;j = Bi,j (i,j = x,y,z)
In Cylindrical coordinates, the physical components of the covariant gradient
tensor are as follows:
Br;r = Br,r
Br;phi = (1/r)Br,phi - Bphi/r
Br:z = Br,z
Bphi;r = Bphi,r
Bphi;phi = (1/r)Bphi,phi + Br/r
Bphi;z = Bphi,z
Bz;r = Bz,r
Bz;phi = (1/r)Bz,phi
Bz;z = Bz,phi
- Version:
- $Id:
- Author:
- Norman A Graf