"介质加热法" can be translated as "dielectric heating method" or "medium heating method" depending on the context.
Dielectric heating method is more commonly used in technical and scientific contexts, especially when referring to the heating of non-conductive materials through the application of an alternating electric field, which causes internal friction and heat generation within the material.
Medium heating method is a more general term that could be used in a broader range of contexts, where "medium" refers to the substance or material through which heat is transferred or in which the heating process occurs.
In most technical and engineering discussions, "dielectric heating method" would be the more precise and commonly used term.