The authors of the present volume have long been recognized for their important contributions to the field of thermionic energy conversion. In the Russian edition of their book they brought together an impressive, coherent description of the physics of the thermionic converter. Their discussion developed carefully from basic principles. The treatment was broad, concise, and well referenced. It is a pleasure to help make this excellent book available to a broader audience by means of this English edition.

The authors report on the physics and applications of thermionic conversion as of 1972. Understanding of the cesium diode converter has not changed significantly since then. However, two of the authors, F.G. Baksht and V.G. Yur'eV, have published a more recent review of this subject (Sov. Phys. - Tech. Phys. 21 531 (1976)), which thus becomes a useful supplement to the present volume. A more recent review of thermionic conversion applications can be found in the proceedings of the latest international conferences on thermionic conversion (see the beginning of Chapter 11).

The thermionic community does not have a universally accepted set of nomenclature and symbols. In this English edition an attempt has been made to retain the nomenclature and symbols of the Russian edition. However, a few exceptions were made where there was a clear advantage for western readers. In the original edition, the authors used the terms cathode and anode almost exclusively, even though the terms emitter and collector are commonly used by their more application-oriented Soviet colleagues. In keeping with the authors’ intent for the book to have general usefulness for the discharge and plasma fields, the English edition uses the terms cathode and anode throughout.

I would like to express appreciation to Glen A. Newby and Owen S. Merrill of the U.S. Energy Research and Development Administration for their interest and support of this project, and especially to Ned S. Rasor for his support and helpful discussions.

L.K. Hansen