Superconductor in inertial fusion targets

Again this message is about inertial fusion.

Inertial fusion tries to make the fusion of deuterium and tritium by implosion of a target irradiated with lasers. This implosion is obtained in an indirect way by the expansion under the impact of lasers of an ablative material that surrounds the mixture D-T. Three important parameters control inertial fusion: density and temperature obtained during the compression and the duration of this dense state before expansion of the plasma.

Some effects limit actually the compression of the target. One of them is particularly annoying: the heating by fast electrons. The heated ablative material emits some fast electrons that penetrate the target. The too early heating generated by these electrons disturbs the compression.

A way to limit the heating of the target by fast electrons could be the use of super conduction by inserting a thin superconductive layer between ablative material and target DT. An outside magnetic field creates in the superconductive material electric currents. These induced currents create a secondary magnetic field that remains when the outside magnetic field is removed. During the irradiation of the ablative material, fast electrons are emitted. Under the influence of the magnetic field present in the superconductive layer, the fast electrons emitted towards the target are deviated by Lorentz force. This deviation of fast electrons could perhaps delay the heating of the target DT.

During the compression, a phenomenon like the formation of the pulsar stars could appear. The conservation of the present magnetic energy in the heart DT implies that during the reduction of the volume the magnetic field is amplified: with B magnetic field and V volume of the heart DT and the superconductive layer, the conservation of the energy implies B^2.V = constant. The increasing of magnetic field by compression could reinforce the shield effect against fast electrons.

The magnetic field remains until one critical parameter (temperature or magnetic field) of superconductive material is reached. Immediately, the energy stored in magnetic field is dissipated in heat form. The duration of this magnetic shield is of course very very short.

The material in this press release comes from the originating research organization. Content may be edited for style and length. Want more? Sign up for our daily email.