plasma fusion reactor is subjected to a necking effect

摘要

889,465. Nuclear fusion reactors. UNITED STATES ATOMIC ENERGY COMMISSION. June 1. 1959 [June 19, 1958], No. 18549/59. Class 39(4) A thermonuclear reactor comprises an elongated gas-tight insulating chamber filled with deuterium and/or tritium, a conductive shell surrounding the chamber, a first electrical means for providing a first axial magnetic field in the chamber, second electrical means connected to the conductive shell for successively ionising the gas to a plasma and compressing and heating the plasma, and a third electrical means for providing a second axial magnetic field in a direction opposed to the first axial magnetic field. The reactor may be toroidal, as shown in the part sectional view of Fig. 4, and comprises an insulating envelope 115 surrounded by a conductive shell 116 made in two halves of semicircular cross - section separated by insulators, of which one 132 is shown in Fig. 4; the shell 116 does not extend right round the toms but has a gap, terminals being attached to the shell at each side of the gap. The shell is surrounded by a cooling jacket supplied with distilled water and by a coil 120 which produces an axial magnetic field; the coil 120 may be a tube through which a coolant is circulated. Inside the envelope 115 is a coil 135 shaped to screen the envelope from the discharge and cooled by distilled water flowing through it; this coil may be short-circuited or connected to an electrical supply, but in either case serves to produce an axial magnetic field in opposition to that produced by coil 120. The reactor may be surrounded by a lithium blanket to produce tritium or by a sub-critical fission reactor. Fig. 8 shows a circuit for operating the reactor. The gas in the reactor is initially ionised by a radio-frequency supply (not shown) applied to diametrically opposed electrodes (not shown) within the toms and circuit 121 is operated to discharge condensers 190 through coil 120. When the current through coil 120 nears its maximum, stage I circuit fires and discharges condensers 200 through shell 116; thereafter in succession stages II, III and IV operate to discharge condensers through the shell to compress and heat the plasma. In the early stages coil 135 (not shown in Fig. 8) is short-circuited and the currents induced in it promote stability of the discharge, but in the final stage the coil is open-circuited; in this final stage the plasma delivers to the circuit energy which may be used to recharge the condensers of stages III and IV. The cycle may last 0.1 second and be repeated at 1 second intervals.