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Updated: May 26, 2026

Experimental Methods of Dust Charging and Mobilization on Surfaces with Exposure to Ultraviolet Radiation or Plasmas
Published on: April 3, 2018
Wakes formed by dust grains in supersonically flowing plasmas
C T N Willis1, J E Allen, M Coppins
1Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BW, United Kingdom.
Abstract:
Interesting wake effects are found in simulations of dust grains in supersonically flowing plasma. A Mach cone is formed at an angle to the flow determined by the ratio of flow to Bohm speed. The latter is well approximated by [k(T(e)+γT(i))/m(i)](1/2) with γ=3. For ion temperatures significantly lower than the electron temperature, a second (inner) cone forms due to flow convergence. An "ion vacuum" and stagnation point occur downstream. These latter effects cannot be described by conventional (cold-ion) gas dynamics. Critically, none of the cones observed are shocks but are more akin to weak discontinuities.
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