Hypergravity effects on glide arc plasma

Abstract

Abstract. The behaviour of a special type of electric discharge -the gliding arc plasma -has been investigated in hypergravity (1g-18g) using the Large Diameter Centrifuge (LDC) at ESA/ESTEC. The discharge voltage and current together with the videosignal from a fast camera have been recorded during the experiment. The gliding of the arc is governed by hot gas buoyancy and by consequence, gravity. Increasing the centrifugal acceleration makes the glide arc movement substantially faster. Whereas at 1g the discharge was stationary, at 6g it glided with 7 Hz frequency and at 18g the gliding frequency was 11 Hz. We describe a simple model for the glide arc movement assuming low gas flow velocities, which is compared to our experimental results.

Translational, rotational, vibrational and electron temperatures of a gliding arc discharge

“…Substantial progress in studying gliding arc discharges has been achieved, including transient discharge processes [30,31], electrical characteristics [32,33], hypergravity effects [34,35] and species distributions [36][37][38], as well as the rotational and vibrational temperatures of gliding arc discharges [25][26][27][28]. However, the translational temperature of the gliding arc discharge has not been directly measured yet up to now.…”

Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge

“…Phenomenological models 21,[32][33][34] were developed to explain the discharge behavior based on accurate measurements of several important parameters, including the slip velocityṼ S (it stands for the relative velocity between the plasma columnṼ C and the gas flowṼ F , and its magnitude is jṼ S j ¼ jṼ C ÀṼ F j), and the length of the plasma column. The slip velocity determines not only the convection cooling efficiency 33 and the drag force 14,35 but also the electric field strength, the power per unit length, and the radius of the conducting zone of the plasma column. 33 The length of the plasma column is used for calculating the electric field strength.…”

“…The drag force F on the plasma column exerted by the turbulent flow is often modelled in the form 14,35 …”

“…With the determination of drag force, the equilibrium velocity of the gliding arc discharge in hyper-gravity, 35 and the magnetic field strength of magnetically stabilized gliding arc discharge under steady state 14 can be calculated. This shows that knowledge of the 3D slip velocity is essential for predicting accurate parameters of the gliding arc discharge.…”

Gravity effects on a gliding arc in four noble gases: from normal to hypergravity

“…The whole experimental setup (except the spectrometer) was placed inside the centrifuge gondola. Given that the detailed description of the experimental apparatus and methods has been presented in [14], only a brief overview follows.…”