System and method for sensing and controlling potential differences between a space object and its space plasma environment using micro-fabricated field emission devices

摘要

A sensor and method for measuring an electrical potential difference are described. The sensor includes a micro-fabricated field emission device situated in a space plasma environment. The field emission device has an emitter terminal and a gate terminal. A voltage source applies a voltage across the gate and the emitter terminals to induce current to flow from the emitter terminal A first current monitor measures current flowing from the emitter in response to the applied voltage. A second current monitor measures current flowing to the gate. A control system correlates applied voltages and measured gate and emitter currents with electrical potential differences between the field emission device and the space plasma environment. The control system obtains the gate and emitter currents from the current monitors. A processor computes a value from the gate and emitter current measurements based on a predetermined functional relationship.