Electro-thermal-chemical (ETC) initiation and combustion offers the possibility to increase the performance of guns substantially as new propellant formulations and high loading densities (HLD) can be safely ignited and burnt in an augmented way. This paper reports investigations of burning phenomena in the low pressure region for JA2 and the effects of plasma interaction on ignition and study its influence on the burning rate. The comparison of transparent and opaque versions of the propellant is of special interest. Electrically produced plasma can strongly influence the ignition and combustion of solid propellants. Predominantly, plasma arcs influence strongly the burning of propellants by its radiation. The high intensity of the radiation initiates burning with short time delays in the mus-range and high conversion during exposure also in the case of a stable burning. Radiation can penetrate into the propellant interior and partially fragment at absorbing structures which could be artificially introduced or be inherently present as in the case of a JA2 propellant. Simplified approaches based on the heat flow equation and radiation absorption can explain these effects at least on a qualitative scale. Dynamic effects are understood by more sophisticated models.