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Bochkarev Sergey Gennad'evich PhD (Physics and Mathematics)
Moscow Leninskiy Prospekt, 53c1 230
Contacts
Publications
2012
- S.G. Bochkarev, G.V. Golovin, D.S. Uryupina, S.A. Shulyapov, A.V. Andriyash, V.Yu Bychenkov, and A.B. Savel\'ev
Effect of a short weak prepulse on laser-triggered front-surface heavy-ion acceleration Physics of Plasmas, vol. 19, N10, pp. 103101, (2012)
аннотация
A suppression of light-ion acceleration (from surface water contaminants) was observed when a moderate-intensity subpicosecond laser pulse was focused on a thick metal target. Simultaneously, an effective generation of high-energy multicharge ions of the target material (Fe) was experimentally observed. A numerical simulation based on the Boltzmann–Vlasov–Poisson model revealed that this is due to the very specific regime of cleaning contaminants from the target surface by the short weak prepulse preceding the main pulse by more than 10 ns and having an intensity below the surface breakdown threshold. Because this prepulse causes the contaminant layer to boil explosively, a low-density gap forms above the target surface. These conditions are consequently favorable for boosting the energy of heavy ions.
2011
- Бочкарев С.Г., Попов К.И., Быченков В.Ю.
ВАКУУМНОЕ УСКОРЕНИЕ ЭЛЕКТРОНОВ РЕЛЯТИВИСТСКИ СИЛЬНЫМ ОСТРОСФОКУСИРОВАННЫМ ЛАЗЕРНЫМ ИМПУЛЬСОМ РАДИАЛЬНОЙ ПОЛЯРИЗАЦИИ Физика плазмы, т. 37, N6, стр. 1-13, (2011)
аннотация
В подходе пробных частиц решена задача о прямом ускорении электронов коротким интенсивным
лазерным импульсом радиальной поляризации для случая, когда размер фокального пятна может
быть порядка длины волны лазера. Для описания полей остросфокусированного лазерного пучка
использованы интегралы Стрэттона-Чу, позволяющие исследовать ускорение электронов в условиях, когда параксиальное приближение для лазерных полей неприменимо. Проанализирована динамика движения электронов в релятивистскисильном радиально поляризованном лазерном поле в зависимости от начального положения частиц в фокальной области лазерного пучка. Также исследованы свойства возникающих струй ускоренных электронов в зависимости от остроты фокусировки лазерного импульса. Обсуждаются преимущества возможного использования лазерных импульсов радиальной поляризации по сравнению со случаем линейной поляризации лазерного излучения для ускорения заряженных частиц.
- Sergey G. Bochkarev, Andrei V. Brantov, Valery Yu. Bychenkov, and Wojciech Rozmus
ULTRASHORT-LASER-PULSE ABSORPTION WITH SPATIAL DISPERSION AND NONLOCAL TRANSPORT EFFECTS Journal of Russian Laser Research, vol. 32, N2, pp. 162, (2011)
аннотация
We study ultrashort-laser-pulse absorption and plasma heating at a sharp plasma–vacuum interface
using advanced models for all-range plasma permittivity and nonlocal heat transport. The electron
response includes both collisional and collisionless dissipative effects in the plasma of an arbitrary ion
charge. We show that nonlocal electron heat transport is important for correct determination of the
value of electron temperature and spatial temperature profile. Nonlocal electron heat flux comes into
play after electrons heat up to temperatures of the order of 1 keV and to temperatures several times
less for low-density targets.
2010
- N. Naseri, S. G. Bochkarev, and W. Rozmus
Self-channelling of relativistic laser pulses in large-scale underdense plasmas Physics of Plasmas, vol. 17, pp. 033107, (2010)
аннотация
Relativistic self-focusing and channelling of intense laser pulses have been studied in underdense plasma using two-dimensional particle-in-cell PIC simulations, for different laser powers and plasma densities. Analytical solutions for the stationary evacuated channels have been recovered in PIC simulations. It is shown that otherwise stable channels can accelerate electrons due to surface waves on the walls of the channels. Relativistic filaments with finite electron density are unstable to
transverse modulations which lead in the nonlinear stage to the breakup of laser pulses into independent filaments. Different regimes of relativistic self-focusing and channelling, including electron heating, transverse instability, and break-up of the filaments, have been discussed and characterized using plasma density and laser power.
2009
Ultrashort laser pulse absorption and target heating AIP Conference Proceedings, vol. 1153, pp. 25-36, (2009)
аннотация
The problem of ultrashort laser pulse absorption at the sharp plasma-vacuum interface has been solved using a new expression for plasma permittivity. The electron response includes both collisional and collisionless dissipative effects in a plasma with arbitrary ion charge. The difference between known absorption models and our theoretical RFBR approach which accounts for localized plasma heating with nonlocal heat transport has been discussed.
- A. V. Brantov, V. T. Tikhonchuk, V. Yu. Bychenkov, and S. G. Bochkarev
Laser-triggered ion acceleration from a double-layer foil Physics of Plasmas, vol. 16, N4, pp. 043107, (2009)
аннотация
A simple analytic model of light-ion acceleration in a double-layer foil target is proposed. It accounts for ion acceleration in the electrostatic sheath and Coulomb interaction between heavy and light ions. The model is used to study proton acceleration, and the conditions for a quasimonoenergetic proton beam formation are defined. Comparison with the hybrid and two-dimensional particle-in-cell kinetic simulations verifies the model results.
2007
- С.Г. Бочкарев, В.Ю. Быченков
Ускорение электронов при острой фокусировке фемтосекундного лазерного излучения Квантовая Электроника, т. 37, N3, стр. 273, (2007)
аннотация
The problem of the acceleration of a test electron
in the éeld of a tightly focused relativistic laser pulse is solved
in the case when the focal spot size is of the order of the
radiation wavelength and the exact solution of Maxwell\'s
equations for the electromagnetic éeld should be used. The
electron acceleration is studied depending on the initial
position of the electron in the focal plane and is compared
with the results corresponding to the paraxial approximation
for the laser field. The maximum energy acquired by the
electron in the laser focus is found. The dependences of the
ejection angle of the electron on its initial position near the
focus are analysed.
2006
- С.Г. Бочкарев, В.Ю. Быченков, В.Т. Тихончук
Исследование ускорения ионов при разлете лазерной плазмы на основе модели Больцмана-Власова-Пуассонна Физика плазмы, т. 32, N3, стр. 370, (2006)
аннотация
The acceleration of ions of different species from a plasma slab under the action of a charge-separation
electric field driven by hot and cold electrons is studied by using a hybrid Boltzmann–Vlasov–Poisson
model. The obtained spatial and energy distributions of light and heavy ions in different charge states demonstrate
that the model can be efficiently used to study the ion composition in a multispecies expanding laser
plasma. The regular features of the acceleration of ions of different species are investigated. The formation of
compression and rarefaction waves in the halo of light ion impurity, as well as their effect on the energy spectrum
of the accelerated ions, is analyzed. An approach is proposed that makes it possible to describe the production
of fast ions by laser pulses of a given shape. It is shown that the energy of fast ions can be increased
markedly by appropriately shaping the pulse. The effect of heating of the bulk of the cold target electrons on
the ion acceleration is discussed.
2005
Ion acceleration in short-laser-pulse interaction with solid foils Plasma Physics and Controlled Fusion, vol. 47, (2005)
аннотация
We discuss the physical processes, which take place in a multi-component
plasma set in expansion by a minority of energetic electrons. The expansion
is in the form of a collisionless rarefaction wave associated with three types
of electrostatic shocks. Each shock manifests itself in a potential jump and
in the spatial separation of plasma species. The shock front associated with
the proton–electron separation sets the maximum proton velocity. Two other
shocks are due to the hot–cold electron separation and the light–heavy ion
separation. They result in the light ion acceleration and their accumulation in
the phase space. These structures open possibilities for control of the number
and the energy spectrum of accelerated ions. Simple analytical models are
confirmed in numerical simulations where the ions are described kinetically,
and the electrons assume the Boltzmann distribution.
2004
Nonequilibrium electron distribution functions and nonlinear thermal transport Physics of Plasmas, vol. 11, N8, pp. 3997-4007, (2004)
аннотация
Quasi-self-similar solutions to the stationary electron kinetic equation in diffusive approximation
have been found in an inhomogeneous plasma. Electron density and temperature corresponding to
these solutions satisfy a steady state plasma profile that is defined by n*T^a=const (a.1). The
derived electron distribution functions describe particle transport, in particular thermal conduction
and ambiporal electric field for the arbitrary amplitude of temperature perturbation in the wide range
of particle collisionality. The quasi-self-similar solutions display enhanced algebraic tails in the
isotropic part and the reduced number of energetic electrons in the anisotropic part of electron
distribution functions. The quasi-self-similar theory of electron kinetics is applied to laser plasma
heating and heat transport into the overdense region. Calculations of the linear Landau damping rate,
growth rate of the return current instability, and dynamical form factor are presented.
Nonequilibrium electron distribution functions and nonlinear thermal transport Physics of Plasmas, vol. 11, N8, pp. 3997-4007, (2004)
аннотация
Quasi-self-similar solutions to the stationary electron kinetic equation in diffusive approximation
have been found in an inhomogeneous plasma. Electron density and temperature corresponding to
these solutions satisfy a steady state plasma profile that is defined by n*T^a=const (a.1). The
derived electron distribution functions describe particle transport, in particular thermal conduction
and ambiporal electric field for the arbitrary amplitude of temperature perturbation in the wide range
of particle collisionality. The quasi-self-similar solutions display enhanced algebraic tails in the
isotropic part and the reduced number of energetic electrons in the anisotropic part of electron
distribution functions. The quasi-self-similar theory of electron kinetics is applied to laser plasma
heating and heat transport into the overdense region. Calculations of the linear Landau damping rate,
growth rate of the return current instability, and dynamical form factor are presented.
2003
Electron acceleration by few-cycle laser pulses with single-wavelength spot size Phys. Rev. E, vol. 67, pp. 026416, (2003)
аннотация
Generation of relativistic electrons from the interaction of a laser pulse with a high density plasma foil,
accompanied by an underdense preplasma in front of it, has been studied with two-dimensional particle-in-cell
~PIC! simulations for pulse durations comparable to a single cycle and for single-wavelength spot size. The
electrons are accelerated predominantly in forward direction for a preplasma longer than the pulse length.
Otherwise, both forward and backward electron accelerations occur. The primary mechanism responsible for
electron acceleration is identified. Simulations show that the energy of the accelerated electrons has a maximum
versus the pulse duration for relativistic laser intensities. The most effective electron acceleration takes
place when the preplasma scale length is comparable to the pulse duration. Electron distribution functions have
been found from PIC simulations. Their tails are well approximated by Maxwellian distributions with a hot
temperature in the MeV range.
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