ENERGY BALANCE OF A HIGH-TEMPERATURE PLASMA INCLUDING THE EFFECT OF MAGNETIC RADIATION

In order to study the possibilities of heating a plasma confined by an external magnetic field, it is necessary to take into account the presence of strong magnetic bremsstrahlung in the millimeter and sub-millimeter wavelength range. The existence of this radiation imposes a limit on the use of the D-D reaction to generate energy exceeding the input energy. In considering this effect, the self-absorption of this radiation should be taken into account. The energy radiated per unit time by an electron moving along helical path in a magnetic field is given by the usual relation dS'/dt = (1) where a)c = \eH/moc\, /? = v/c and the other symbols have their usual meaning. Assuming that electrons have a Maxwell distribu-tion, the total radiated energy per unit time per unit volume is QM = {4e2l3c)(TG/mc2)œc2ne X (1 + 5Te¡2mc2 +...) (2) where ne and Te are the electron density and tem-perature, respectively. Let us examine first the case when self-absorption may be neglected and all this radiation will escape the plasma. This escape of energy proves to be rather considerable at thermonuclear temperatures. In Fig. 1 we compare curves for the escape of magnetic radiation without self-absorption, the normal brems-strahlung, and the energy release by D-D and D-T reactions, as functions of the temperature for the following conditions T T- — T •L e — J i = •*• ne = щ = n (3) We have use