Short circuit current of thermoionic energy converter by resonance light irradiation

A thermoionic energy conversion is one of the methods of direct electricity generation. The space charge effect, which limits the space emission, is relaxed by enclosing cesium in the converter. In general, the converter is operated at high emitter temperature because of the production of cesium ion by contact thermal ionization. The high operating temperature causes short emitter lifetime which becomes a problem in terms of practical use. The converter is irradiated with the resonance light so that cesium ion is produced by photoionization. It is seen that the output resulting from the resonance light irradiation is much higher than that resulting from the visible light. Many cesium ions can be produced in the space between the electrodes since most of the resonance light is absorbed by cesium atoms. The maximum value of the short circuit current density is about 1kA/m2. It is found that resonance light irradiation is one of the effective methods suitable for practical application. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(1): 14–21, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10250