Magnetic self-insulation of vacuum transmission lines

The heating of pellets to produce nuclear fusion using 10
¹⁴
- 10
¹⁵
Wt electron beams [1] can be achieved only if the beams are focused to a small region less than 1 - 10 cm in size. The problem can not be solved by simply placing a conventional accelerator diode near to the focusing region. In fact, the diode-power source dielectric diaphragm cannot transmit energy fluxes in excess of 10
⁷
- 10
⁹
Wt/cm
²
without flashover of vacuum surface [2]. Consequently, for a beam power of 10
¹³
- 10
¹⁵
Wt the diaphragm area should be 10
⁵
- 10
⁷
cm
²
. It follows that the diode has to be separated from the pellet by a distance of several meters. The requirement to transport energy over this distance can be met by means of passing the beam through plasma. However, at the currents of 10
⁷
- 10
⁸
A the focusing and transport are complicated by the too large angular spread of the beam.