The molecular dynamics method is used to simulate the formation of ultracold plasma under continuous ionizing irradiation in a quadrupole magnetic field with the gradient of the magnetic field along ...the axis of symmetry equal to 0, 30, 150, and 500 G/cm. An increase in the magnetic field promotes an increase in the plasma density owing to the trapping of some part of fast electrons by the quadrupole magnetic field.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The formation of a two-component steady-state nonideal ultracold plasma using an ionizing cw laser is directly simulated. It is shown that, in much the same way as the case of pulse ionization, the ...formation of steady-state plasma is determined by the electric field created by fast electrons leaving the plasma. This field accelerates ions and keeps remaining electrons within the plasma. In this case, continuous ionization results in the fast formation of a steady-state density and temperature distribution of plasma particles, which can exist for a long time, at a certain time, which depends on the initial energy of electrons and ions, as well as on the plasma density.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
Using the method of molecular dynamics, the expansion of a two-component, pulsed laser-produced ultracold plasma is directly calculated for various values of the number and density of ...particles and their electron temperatures. A new method is presented for generating and diagnosing a steady-state ultracold plasma formed under continuous wave laser irradiation. The performed calculations show the difference in the properties of an ultracold plasma obtained by pulsed and continuous wave laser irradiation.
We present simulation results of ultracold Sr plasma expansion in a quadrupole magnetic field by means of molecular dynamics. An analysis of plasma evolution influenced by a magnetic field is given. ...Plasma confinement time behavior under variation of magnetic field strength is estimated. Similarity of the time dependence of the concentration and distribution of ion velocities against the parameters of the plasma and magnetic field is established. Simulation results are in agreement with the experimental ones.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
The tensor analyzing power components T20 and T21 have been measured in elastic electron-deuteron scattering at the 2 GeV electron storage ring VEPP-3, Novosibirsk, in a four-momentum transfer range ...from 8.4 to 21.6 fm(-2). A new polarized internal gas target with an intense cryogenic atomic beam source was used. The new data determine the deuteron form factors G(C) and G(Q) in an important range of momentum transfer where the first node of the deuteron monopole charge form factor is located. The new results are compared with previous data and with some theoretical predictions.
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This work is devoted to the molecular dynamic calculations of the properties of technical gases, whose study is a traditional problem of physics of matter. At present, there is increased interest in ...this problem due to the development of nanotechnologies and their introduction in various industries. The gases’ properties required for simulation are expressed as a set of macroparameters, including kinetic coefficients; parameters of the equation of state; and values of kinetic, potential, total, and internal energies. The study was performed for technical gases such as argon, hydrogen, nitrogen, and methane at a pressure of 1 atm and in the temperature range from 100 to 400 K. The obtained calculated data on the macroparameters of gases is in good agreement with the known theoretical estimates and experimental data.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
10.
The HERMES recoil detector Airapetian, A; Aschenauer, E C; Belostotski, S ...
Journal of instrumentation,
05/2013, Volume:
8, Issue:
5
Journal Article
Peer reviewed
Open access
For the final running period of HERA, a recoil detector was installed at the HERMES experiment to improve measurements of hard exclusive processes in charged-lepton nucleon scattering. Here, deeply ...virtual Compton scattering is of particular interest as this process provides constraints on generalised parton distributions that give access to the total angular momenta of quarks within the nucleon. The HERMES recoil detector was designed to improve the selection of exclusive events by a direct measurement of the four-momentum of the recoiling particle. It consisted of three components: two layers of double-sided silicon strip sensors inside the HERA beam vacuum, a two-barrel scintillating fibre tracker, and a photon detector. All sub-detectors were located inside a solenoidal magnetic field with a field strength of 1 T. The recoil detector was installed in late 2005. After the commissioning of all components was finished in September 2006, it operated stably until the end of data taking at HERA end of June 2007. The present paper gives a brief overview of the physics processes of interest and the general detector design. The recoil detector components, their calibration, the momentum reconstruction of charged particles, and the event selection are described in detail. The paper closes with a summary of the performance of the detection system.
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