I need to know if nuclear material equal in volume to two marbles could be reacted in a way to cause an EMP that would disrupt an average complexity computer system (e.g. laptop). My suspicious is that this wouldn't reach critical mass, wouldn't create a chain reaction, and .'. no EMP. But I have no idea what aspect of nuclear reactions cause EMPs. Even if this is an ambiguous area of theory, I get the feeling that my question has been clearly answered experimentally. Thanks!