Artificially killing particles

For example for doing cylindrically symmetric simulations of an H- extraction, where electrons are dumped at some location, you can artificially kill the particles at some location. For that you need to define a callback functor:

class THCallback : public TrajectoryHandlerCallback {
public:

    THCallback() {}

    virtual ~THCallback() {}

    virtual void operator()( ParticleBase *particle, ParticlePBase *xcur, ParticlePBase *xend ) const {
        ParticlePCyl *pcur = (ParticlePCyl *)( xcur );
        ParticlePCyl *pend = (ParticlePCyl *)( xend );
        // Kill particles with mass less than 0.5 atomic mass and x-coordinate more than 3 mm.
        if( particle->m() < 0.5*MASS_U && (*pcur)[PARTICLE_X] >= 3.0e-3 ) {
            *pend = *pcur;
            particle->set_status( PARTICLE_COLL );
        }
    }
};

Then you need to add this callback to the particle database:

THCallback thc;
pdb.set_trajectory_handler_callback( &thc );