Erosion Of Plasma-exposed Surfaces In An Electrothermal Accelerator

Erosion of material surfaces exposed to high heat fluxes produced by plasmas in electrothermal accelerators has been studied. The incident heat flux varies between 5x10
⁹
to 4 x 10
¹⁰
W/m
²
over 100 μsec duration, for input energies 1-5 kJ. The plasma produced in electrothermal and electromagnetic accelerators with such high heat loading will cause surface damage. Erosion of the critical components in these devices must be minimized in order to maximize device efficiency and its lifetime. Erosion of different materials has been studied using an electrothermal accelerator, SIRENS, capable of producing such high heat loading. The experimental facility, SIRENS, can produce high-density (10
²⁵
-10
²⁶
/m
³
) low-temperature (1-3 eV) plasma, formed by the ablation of the insulator (Lexan), with currents up to 100 kA. The plasma is allowed to flow through a cylindrical stainless steel barrel which contains the test material. The test material is of tubular shape and may be arranged as one single piece or split into 10 identical pieces to obtain axial measurements of erosion. The plasma boundary layer absorbs the incoming energy and prevents it from reaching the surface, and thus it is referred to as the "vapor shield".