Program Listing for File ArchimedeanSpiralField.cpp

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#include "crpropa/magneticField/ArchimedeanSpiralField.h"

namespace crpropa {

ArchimedeanSpiralField::ArchimedeanSpiralField(double B_0, double R_0, double Omega, double V_w) {
        setB0(B_0);
        setR0(R_0);
        setOmega(Omega);
        setVw(V_w);
}

Vector3d ArchimedeanSpiralField::getField(const Vector3d &pos) const {

        double r = pos.getR();
        double theta = pos.getTheta();
        double phi =pos.getPhi();

        double cos_phi = cos(phi);
        double sin_phi = sin(phi);
        double cos_theta = cos(theta);
        double sin_theta = sin(theta);

        Vector3d B(0.);

        // radial direction
        double C1 = R_0*R_0/r/r;
        B.x += C1 * cos_phi * sin_theta;
        B.y += C1 * sin_phi * sin_theta;
        B.z += C1 * cos_theta;

        // azimuthal direction
        double C2 = - (Omega*R_0*R_0*sin_theta) / (r*V_w);
        B.x += C2 * (-sin_phi);
        B.y += C2 * cos_phi;

        // magnetic field switch at z = 0
        if (pos.z<0.) {
                B *= -1;
        }

        // overall scaling
        B *= B_0;


        return B;
}

void ArchimedeanSpiralField::setR0(double R) {
        R_0 = R;
        return;
}

void ArchimedeanSpiralField::setB0(double B) {
        B_0 = B;
        return;
}

void ArchimedeanSpiralField::setOmega(double Om) {
        Omega = Om;
        return;
}

void ArchimedeanSpiralField::setVw(double v) {
        V_w = v;
        return;
}


double ArchimedeanSpiralField::getR0() const {
        return R_0;
}

double ArchimedeanSpiralField::getB0() const{
        return B_0;
}

double ArchimedeanSpiralField::getOmega() const{
        return Omega;
}

double ArchimedeanSpiralField::getVw() const {
        return V_w;
}


} //end namespace crpropa