This variable selects the level of Maxwell-matter coupling.
Options:
none:
No coupling.
length_gauge_dipole:
Coupling at dipole level in length gauge with transverse electric field E(t). The option MaxwellDipoleField
should be set (by default, dipole coupling with the average electric field will be used)
velocity_gauge_dipole:
Coupling at dipole level in velocity gauge with transverse vector potential A(t). The option MaxwellDipoleField
should be set.
full_minimal_coupling:
Full vector potential A(r,t) coupled to the momentum.