Choice of targets for inertial confinement fusion

We propose a simple target in the form of a miniature torus, in which the heavy shell is used to confine the plasma spread, for a solution of the laser-fusion problem. We achieve a significant decrease of heat losses using an external magnetic field and/or as a result of a self-sustaining magnetic field that is generated in the plasma. We formulate the conditions and determine the energy of the laser pulse (or of a beam of fast charged particles) required to ignite a thermonuclear DD reaction and obtain a positive energy yield. We show that the stopping range of α-particles does not exceed the small radius of the torus within a broad range of the plasma and magnetic-field parameters.