XXXI conference on plasma physics and CF, February 16 – 20, 2004, Zvenigorod
THE INTERACTION POTENTIAL OF TWO CHARGED DUST PARTICLES IN
PLASMAS
D.N. Gerasimov, O.A. Sinkevich
Moscow Power Engineering Institute, Moscow, Russia, e-mail: oleg.sinkevich@itf.mpei.ac.ru
Earlier in our work [1], the analytical expression for the potential of interaction of two charged
dust particles in partly ionized gas was received. Received potential takes into account influence not
only interactions of dust particles but also influence of electron and ion clouds that are surrounding
particles.
U(r) = U0[2(1 + Xs + Xs2 )s-1 - exp(xs)]exp(-s)
(1)
Here U0 = 3 kTNDs2xs2 = qs2/80rD, xs = rd /rD is dimensionless radius of a dust, rD is the
Debye radius, s = r/rD is the dimensionless distance between centers of dusts, ND = (4/3) rD3 n0 is
number of particles in Debye’s sphere, qs is the charge of a dust, s is the surface electrical
potential of a dust.
Potential (1) is not monotonous, has a minimum, which is situated
rd /rD 1 + 3.
(2)
= Umin/kT = qs2/0rD kT > 1400.
(3)
The plasma non - ideality is
The presence of the potential well depth testifies to an opportunity of formation in plasmas of the
bound state for two particles carrying an identical electrical charge. Numerical experiments [2]
have also confirmed similar non - monotonous changing of the potential of interaction of charged
dust particle in plasma.
It is possible using the Vlasov criterion of the crystal formation and the potential (1) one could
find the next scaling for the charged dust crystal formation
Zd = (20kBT/3 e)1\2 rd nd1\2.
(4)
The condition (4) connects the charge of a dust particle, its radius, the density of dust particles,
and temperature of plasma and differs from known Lindemann’s criterion.
Referenses.
[1]. Gerasimov D.N., Sinkevich O.A.. Formation of Ordered Structures in Thermal Dusty Plasma.
High Temperature 1999, Vol. 37, No 6, pp. 823-827.
[2]. Иньков Л.В.. Численное моделирование кинетических процессов в пылевой плазме.
Диссертация канд.ф.-м.н., 2003, МФТИ.
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