Dr. Sergey A. Khrapak
Insttitut for Materials Physics in Space, German Aerospace Center (DLR)
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Academic Career Length
30Years (1997-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications1 December 2005 in Physics Reports
Journal Article
VFV Fortov
V Fortov
AIA Ivlev
A Ivlev
Sergey A. Khrapak
Алексей ХрапакGMG Morfill
G Morfill
31 May 2004 in Physics-Uspekhi
Journal Article
VFVladimir E Fortov
Vladimir E Fortov
Алексей ХрапакSergey A. KhrapakVMVladimir I Molotkov
Vladimir I Molotkov
OPOleg F Petrov
Oleg F Petrov
21 October 2002 in Physical Review E
Journal Article
Sergey A. KhrapakAIA. V. Ivlev
A. V. Ivlev
GMG. E. Morfill
G. E. Morfill
HTH. M. Thomas
H. M. Thomas
The problem of calculating the ion drag force in complex plasmas is considered. It is shown that the standard theory of Coulomb scattering usually fails for the ion-dust elastic collisions. A simple approach to extend this theory is proposed. This leads to a considerable enhancement in the ion-dust elastic scattering cross section and, hence, increases the ion drag force in comparison with the previous analytical results. Analysis shows that the ion drag usually exceeds the electrostatic force in the limit of weak electric field. We suggest that this is the cause of the central “void” observed in microgravity complex plasma experiments.
28 July 2005 in Physical Review E
Journal Article
Sergey A. KhrapakSRS. V. Ratynskaia
S. V. Ratynskaia
AZA. V. Zobnin
A. V. Zobnin
AUA. D. Usachev
A. D. Usachev
VYV. V. Yaroshenko
V. V. Yaroshenko
VFV. E. Fortov
V. E. Fortov
+5
An experimental determination of particle charge in a bulk dc discharge plasma covering a wide range of neutral gas pressures, was recently reported [S. Ratynskaia et al., Phys. Rev. Lett. 93, 085001 (2004)]. The charges obtained were several times smaller than the predictions of collisionless orbital motion limited theory. This discrepancy was attributed to the effect of ion-neutral collisions. In the present paper a more detailed description of this experiment is provided and additional experimental results obtained with particles of different sizes are reported. The measurements are compared with molecular dynamics simulations of particle charging for conditions similar to those of the experiment, with other available experimental data on particle charge in the bulk of gas discharges, and with a simple analytical model accounting for ion-neutral collisions. All the considered evidence indicates that ion-neutral collisions represent a very important factor, which significantly affects (reduces) the particle charge under typical discharge conditions.
6 June 2003 in Physical Review Letters
Journal Article
Sergey A. KhrapakAIA. V. Ivlev
A. V. Ivlev
GMG. E. Morfill
G. E. Morfill
SZS. K. Zhdanov
S. K. Zhdanov
Scattering in the attractive screened Coulomb (Yukawa) potential in the limit of strong interaction is investigated. It is shown that the scattering occurs mostly with large angles. The corresponding momentum-transfer cross section is calculated. The results are applied to estimate the ion drag force acting on an isolated micron-sized grain in low-pressure bulk plasmas.
1 March 2008 in New Journal of Physics
Journal Article
HTH M Thomas
H M Thomas
GMG E Morfill
G E MorfillVFV E Fortov
V E Fortov
AIA V Ivlev
A V Ivlev
VMV I Molotkov
V I Molotkov
SKS K Krikalev
S K Krikalev
+8
About Me
Sergey Khrapak received the M.Sc. and Ph.D. degrees in physics from the Moscow Institute of Physics and Technology (State University) in 1996 and 1999, respectively. From 1996, he was a Research Fellow and then Senior Scientist with the Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow. From 2000 to 2013, he was with the Theory (complex plasma) Group at the Max-Planck Institute for Extraterrestrial Physics, Garching, Germany. From 2014 to 2021, he was with the Complex Plasma Group at the German Aerospace Centre (DLR), Wessling, Germany. From 2015 to 2018, he was also appointed as Chair of Excellence at PIIM Laboratory, Aix-Marseille-University, Marseille, France. In 2020–2022, he was a PI of the project titled “Collective dynamics, elastic and transport properties of classical fluids in different regimes of interparticle interaction” at Bauman Moscow State Technical University. He is the author of more than 200 scientific papers. His current scientific interests are mostly focused on the theory of complex (dusty) plasmas, soft condensed matter, and physics of fluids.