Ion acceleration in vacuum arc cathode plasma jets with large rates of current rise

A general expression for ion-ion coupling in a multi-species plasma jet was obtained. The expression is valid for any value of the inter-species velocity. This expression has enabled us to review a hydrodynamic problem of expanding the cathodic plasma microjet with two ion species within the respective charge states Z1 = +1 and Z2 = +2 into a vacuum. We were able to illustrate that in scenario when the initial (i.e., acquired during a process of emission from cathode's surface) difference for ion's species velocity exceeds a threshold value, the difference remains noticeable (roughly about 10% of the average jet's velocity) at a distance of a few centimeters from the emission center. At this point, it can be measured experimentally.

show abstract

Ion acceleration at different stages of a pulsed vacuum arc

Paperny¹,

Chernich²,

Astrakchantsev³

et al. 2009

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Detailed measurements of ion energy distributions (IEDs) originating at different stages of a pulsed vacuum arc are studied. It is shown that for a variety of cathode materials (Al, Mg, Ti and Zr), the directed energies per charge unit of ion originating at the initial stage of the arc, i.e. in 25 µs after ignition, are close to each other and are, approximately, as much as Edir/Z ≈ 70 eV. A non-Maxwellian shape of these IEDs that is due to the presence of significant ‘tails’ of ions accelerated up to energies of a few hundred eletronvolts is found. In 100 µs after the arc ignition the directed energies relax to values that are close, principally, to values that have been measured earlier elsewhere. It is found that the ‘anomalously’ accelerated ions propagate within a narrow angle that is as much as, approximately, ±15° in relation to the plasma flux axis. These characteristics suggest that beyond the commonly adopted gas-dynamic mechanism of ion acceleration in cathode micro-jets, at the initial stage of a pulsed arc the mechanism of additional ion acceleration is presented, which is due, obviously, to a self-consistent electric field arising in front of the plasma macro-jet.

show abstract

Ion acceleration in vacuum arc cathode plasma jets with large rates of current rise

Cited by 8 publications

References 12 publications

Spot Plasma and Plasma Jet

Spot Plasma and Plasma Jet

Ion acceleration in multi-species cathodic plasma jet

Ion acceleration at different stages of a pulsed vacuum arc

Contact Info

Product

Resources

About