Speaker
Victor Désangles
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/O4.J501.pdf
Emissive cathode biasing controls drift velocities in a plasma column
V. Désangles1 , G. Bousselin1 , A. Poyé1 , M. Moulin1 , V. Dolique1 , L. de Poucques2 , N. Plihon1
1 Univ Lyon, Ens de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique UMR 5672,
F-69342, Lyon, France
2 Université de Lorraine, CNRS, Institut Jean Lamour UMR 7198, F-54506,
Vandoeuvre-lès-Nancy, France
Controlling drift velocities in a plasma column is essential for various applications: to de-
velop plasma centrifuges [1], to master drift waves and electrostatic turbulence and to miti-
gate anomalous transport [2] , to study astrophysical mechanisms [3] and to study flow re-
lated instabilities in ionospheric like plasmas [4]. So far, only cold conductive biased electrodes
2500
Cath. ON meas. such as concentric rings, end plates
2000 Cath. ON fit (a)
Cath. OFF fit
(b) or grids have been used to try
1500
Cath.OFF meas. B
1000
Velocity (m.s-1 )
500 to control plasma flows in linear
0
-500
plasma experiments. These setups
-1000
to be efficient in controlling the
-1500
-2000
Emissive plasma parameters profiles, how-
-2500 Cathode
4 3 2 1 0 -1 -2 -3 -4
Radial Location (cm) ever they are limited by the strong
Debye shielding in plasmas.
Figure 1: (a.) Measured ion velocity for two cases: cathode
We report here a new tool to con-
floating at plasma potential (blue) and biased and emitting
trol drift velocities. Using a nega-
electrons (orange); (b.) Schematic drawing of the stirring setup
tively biased hot emissive cathode
(fig1.b.), we show the ability to control Vp and ne profiles by injecting locally strong elec-
tron currents into the plasma. Direction, shear and amplitude of the plasma flow profile can also
be controlled changing the cathode location and the intensity of the injected current (fig1.a.).
These modifications of the plasma equilibrium have been studied extensively using Langmuir
probes, emissive probes, mach probes and LIF measurements. We show that the rotation pro-
files may be explained by electric and diamagnetic drifts and are directly related to the amount
of current emitted by the cathode.
References
[1] Gueroult, R. et al., Plasma Sources Sci. Technol., 25, 35024 (2016).
[2] Gilmore, M. et al., J. Plasma Phys., 81, 345810104 (2015). Thakur, S. C. et al. Phys. Plasmas, 23,
082112 (2016). Dubois, A. et al., Phys. Plasmas, 21, 062117 (2014)
[3] Terasaka, K. et al., J. Plasma Phys., 81, 345810101 (2015).
[4] Eadon, A. C. et al., Rev. Sci. Instrum., 82, 63511 (2011).
