Tornado-type closed magnetic trap for an electron cyclotron resonance ion source

Abstract

We propose to use a Tornado-type closed magnetic trap for creation of a source of multicharged ions with plasma heating by microwave radiation. Plasma loss in closed traps is determined by diffusion across the magnetic field, which increases substantially plasma confinement time as compared to the classical mirror trap. The Tornado trap also possesses merits such as: an opportunity to produce high magnetic fields up to 3 T, which makes possible heating and confinement of plasma with a high density of electrons; an opportunity to use supplementary coils for ion extraction; plasma stability to magnetohydrodynamic perturbations because the magnetic field structure corresponds to the “min B” configuration; and relatively low costs. All estimates and calculations were carried out for the existing Tornado-322 pulse installation (maximal magnetic field 2.8 T) with plasma heating at 53 GHz frequency. The numerical simulation has shown that, by the end of the magnetic field pulse, ion distribution over charge states may reach a maximum at Ar+16 for the plasma density of 1013 cm−3. The current density of ions Ar+16 can be varied from 10 mA/cm2 to approximately 1 A/cm2.