Energy conversion with stacks of nanocapacitors

Methods and apparatus for converting kinetic energy of an energetic particle into electrical energy and for accelerating charged particles. A stack of substantially parallel conductors separated by gaps is disposed such that the conductors are substantially parallel to the surface of a cathode, with the conductors mutually electrically uncoupled. An anode is disposed at an end of the stack of conductors distal to the cathode, and a power management system applies a bias voltage between the cathode and the anode and collects charge deposited at the anode in the form of current in an external electrical circuit.