34 research outputs found
The reflectivity of relativistic ultra-thin electron layers
The coherent reflectivity of a dense, relativistic, ultra-thin electron layer
is derived analytically for an obliquely incident probe beam. Results are
obtained by two-fold Lorentz transformation. For the analytical treatment, a
plane uniform electron layer is considered. All electrons move with uniform
velocity under an angle to the normal direction of the plane; such electron
motion corresponds to laser acceleration by direct action of the laser fields,
as it is described in a companion paper. Electron density is chosen high enough
to ensure that many electrons reside in a volume \lambda_R^3, where \lambda_R
is the wavelength of the reflected light in the rest frame of the layer. Under
these conditions, the probe light is back-scattered coherently and is directed
close to the layer normal rather than the direction of electron velocity. An
important consequence is that the Doppler shift is governed by
\gamma_x=(1-(V_x/c)^2)^{-1/2} derived from the electron velocity component V_x
in normal direction rather than the full \gamma-factor of the layer electrons.Comment: 7 pages, 4 figures, submitted to the special issue "Fundamental
Physics with Ultra-High Fields" in The European Physical Journal
Acceleration of ultra-thin electron layer. Analytical treatment compared with 1D-PIC simulation
In this paper, we apply an analytical model [V.V. Kulagin et al., Phys.
Plasmas 14,113101 (2007)] to describe the acceleration of an ultra-thin
electron layer by a schematic single-cycle laser pulse and compare with
one-dimensional particle-in-cell (1D-PIC) simulations. This is in the context
of creating a relativistic mirror for coherent backscattering and supplements
two related papers in this EPJD volume. The model is shown to reproduce the
1D-PIC results almost quantitatively for the short time of a few laser periods
sufficient for the backscattering of ultra-short probe pulses.Comment: 4 pages, 4 figures, submitted to the special issue "Fundamental
Physics with Ultra-High Fields" in The European Physical Journal
Coulomb implosion mechanism of negative ion acceleration in laser plasmas
Coulomb implosion mechanism of the negatively charged ion acceleration in
laser plasmas is proposed. When a cluster target is irradiated by an intense
laser pulse and the Coulomb explosion of positively charged ions occurs, the
negative ions are accelerated inward. The maximum energy of negative ions is
several times lower than that of positive ions. The theoretical description and
Particle-in-Cell simulation of the Coulomb implosion mechanism and the evidence
of the negative ion acceleration in the experiments on the high intensity laser
pulse interaction with the cluster targets are presented.Comment: 4 page
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam
Laser wakefield acceleration has the possibility to generate an ultrashort electron beam of the order of femtoseconds or less. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse (optical injection). Stable and monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration by using a Nitrogen gas jet target. The electron interaction with the laser field results in transverse oscillations of the electron beam. From the electron oscillation period dependence on the electron energy we find that the electron beam width is equal to 1.7 fs (rms).Π ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΡΡΠΊΠΎΡΠ΅Π½ΠΈΡ ΠΊΠΈΠ»ΡΠ²Π°ΡΠ΅ΡΠ½ΡΠΌΠΈ Π²ΠΎΠ»Π½Π°ΠΌΠΈ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½Π° Π³Π΅Π½Π΅ΡΠ°ΡΠΈΡ ΡΠ²Π΅ΡΡ
ΠΊΠΎΡΠΎΡΠΊΠΈΡ
ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΡ
ΠΏΡΡΠΊΠΎΠ² ΡΠ΅ΠΌΡΠΎΡΠ΅ΠΊΡΠ½Π΄Π½ΠΎΠΉ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡΡ. ΠΠ»Ρ ΠΏΡΠΈΠ»ΠΎΠΆΠ΅Π½ΠΈΠΉ ΡΡΠ΅Π±ΡΡΡΡΡ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΠ΅ ΠΏΡΡΠΊΠΈ Ρ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΡΠΌΠΈ ΠΈ ΠΊΠΎΡΡΠΎΠ»ΠΈΡΡΠ΅ΠΌΡΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ. ΠΠΏΡΠΈΡΠ΅ΡΠΊΠ°Ρ ΠΈΠ½ΠΆΠ΅ΠΊΡΠΈΡ, ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΠ°Ρ ΡΡΠ°Π»ΠΊΠΈΠ²Π°ΡΡΠΈΠ΅ΡΡ Π»Π°Π·Π΅ΡΠ½ΡΠ΅ ΠΈΠΌΠΏΡΠ»ΡΡΡ, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°Π΅Ρ Π²ΡΡΠΎΠΊΡΡ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΏΡΡΠΊΠΎΠ² ΡΡΠΊΠΎΡΠ΅Π½Π½ΡΡ
ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ². ΠΠΎΠ½ΠΎΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΡΡΠΊΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ² Ρ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΡΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ Π±ΡΠ»ΠΈ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ ΠΏΡΠΈ Β«ΡΠ°ΠΌΠΎΠΈΠ½ΠΆΠ΅ΠΊΡΠΈΠΈΒ» Π² ΠΊΠΈΠ»ΡΠ²Π°ΡΠ΅ΡΠ½ΡΡ Π²ΠΎΠ»Π½Ρ Π² ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Ρ
, ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΠΈΡ
Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΌΠΈΡΠ΅Π½ΠΈ ΡΡΡΡΡ Π°Π·ΠΎΡΠ°. ΠΠ·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ² Ρ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΠ΅ΠΌ Π»Π°Π·Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠΌΠΏΡΠ»ΡΡΠ° ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ ΠΊ ΠΏΠΎΠΏΠ΅ΡΠ΅ΡΠ½ΡΠΌ ΠΎΡΡΠΈΠ»Π»ΡΡΠΈΡΠΌ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°. ΠΠ½Π°Π»ΠΈΠ· Π½Π°Π±Π»ΡΠ΄Π°Π΅ΠΌΠΎΠΉ Π² ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ΅ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΏΠ΅ΡΠΈΠΎΠ΄Π° ΠΎΡΡΠΈΠ»Π»ΡΡΠΈΠΉ ΠΎΡ ΡΠ½Π΅ΡΠ³ΠΈΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ² ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ Π½Π°ΠΉΡΠΈ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°, ΡΠ°Π²Π½ΡΡ 1.7 ΡΡ.Π ΠΏΡΠΎΡΠ΅ΡΡ ΠΏΡΠΈΡΠΊΠΎΡΠ΅Π½Π½Ρ ΠΊΡΠ»ΡΠ²Π°ΡΠ΅ΡΠ½ΠΈΠΌΠΈ Ρ
Π²ΠΈΠ»ΡΠΌΠΈ ΠΌΠΎΠΆΠ»ΠΈΠ²Π° Π³Π΅Π½Π΅ΡΠ°ΡΡΡ Π½Π°Π΄ΠΊΠΎΡΠΎΡΠΊΠΈΡ
Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΈΡ
ΠΏΡΡΠΊΡΠ² ΡΠ΅ΠΌΡΠΎΡΠ΅ΠΊΡΠ½Π΄Π½ΠΎΡ ΡΡΠΈΠ²Π°Π»ΠΎΡΡΡ. ΠΠ»Ρ Π΄ΠΎΠ΄Π°ΡΠΊΡΠ² ΠΏΠΎΡΡΡΠ±Π½Ρ Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½Ρ ΠΏΡΡΠΊΠΈ Π· Π²ΡΠ΄ΡΠ²ΠΎΡΡΡΡΠΈΠΌΠΈ Ρ ΠΊΠΎΡΡΠΎΠ»ΡΡΡΠΈΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ. ΠΠΏΡΠΈΡΠ½Π° ΡΠ½ΠΆΠ΅ΠΊΡΡΡ, ΡΠΎ Π²ΠΈΠΊΠΎΡΠΈΡΡΠΎΠ²ΡΡ Π·ΡΡΡΠΎΠ²Ρ
ΡΡΡΡ Π»Π°Π·Π΅ΡΠ½Ρ ΡΠΌΠΏΡΠ»ΡΡΠΈ, Π·Π°Π±Π΅Π·ΠΏΠ΅ΡΡΡ Π²ΠΈΡΠΎΠΊΡ Π²ΡΠ΄ΡΠ²ΠΎΡΡΠ²Π°Π½ΡΡΡΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡΠ² ΠΏΡΡΠΊΡΠ² ΠΏΡΠΈΡΠΊΠΎΡΠ΅Π½ΠΈΡ
Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ². ΠΠΎΠ½ΠΎΠ΅Π½Π΅ΡΠ³Π΅ΡΠΈΡΠ½Ρ ΠΏΡΡΠΊΠΈ Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ² Π· Π²ΡΠ΄ΡΠ²ΠΎΡΡΠ²Π°Π½ΠΈΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ Π±ΡΠ»ΠΈ ΠΎΡΡΠΈΠΌΠ°Π½Ρ ΠΏΡΠΈ Β«ΡΠ°ΠΌΠΎΡΠ½ΠΆΠ΅ΠΊΡΡΡΒ» Π² ΠΊΡΠ»ΡΠ²Π°ΡΠ΅ΡΠ½Ρ Ρ
Π²ΠΈΠ»Ρ Π² Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Ρ
, Π² ΡΠΊΠΈΡ
Π² ΡΠΊΠΎΡΡΡ ΠΌΡΡΠ΅Π½Ρ Π²ΠΈΠΊΠΎΡΠΈΡΡΠΎΠ²ΡΠ²Π°Π»Π°ΡΡ ΡΡΡΡΠΌΡΠ½Ρ Π°Π·ΠΎΡΡ. ΠΠ·Π°ΡΠΌΠΎΠ΄ΡΡ Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ² Π· Π²ΠΈΠΏΡΠΎΠΌΡΠ½ΡΠ²Π°Π½Π½ΡΠΌ Π»Π°Π·Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΠΌΠΏΡΠ»ΡΡΡ ΠΏΡΠΈΠ·Π²ΠΎΠ΄ΠΈΡΡ Π΄ΠΎ ΠΏΠΎΠΏΠ΅ΡΠ΅ΡΠ½ΠΈΡ
ΠΎΡΡΠΈΠ»ΡΡΡΠΉ Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°. ΠΠ½Π°Π»ΡΠ· ΡΠΏΠΎΡΡΠ΅ΡΡΠ³Π°ΡΡΠΎΡ Π² Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΡ Π·Π°Π»Π΅ΠΆΠ½ΠΎΡΡΡ ΠΏΠ΅ΡΡΠΎΠ΄Ρ ΠΎΡΡΠΈΠ»ΡΡΡΠΉ Π²ΡΠ΄ Π΅Π½Π΅ΡΠ³ΡΡ Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ² Π΄ΠΎΠ·Π²ΠΎΠ»ΡΡ Π·Π½Π°ΠΉΡΠΈ ΡΡΠΈΠ²Π°Π»ΡΡΡΡ Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°, ΡΠΊΠ° Π΄ΠΎΡΡΠ²Π½ΡΡ 1.7 ΡΡ
Observation of Burst Intensification by Singularity Emitting Radiation generated from relativistic plasma with a high-intensity laser
Coherent x-rays via the Burst Intensification by Singularity Emitting Radiation (BISER) mechanism are generated from relativistic plasma in helium gas target. A broad modulation of the BISER spectrum, which is significantly wider than the harmonic order, is observed and characterized. In particular, we found that the modulation period can be as large as 41 eV
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X-ray emission from stainless steel foils irradiated by femtosecond petawatt laser pulses
We report about nonlinear growth of x-ray emission intensity emitted from plasma generated by femtosecond petawatt laser pulses irradiating stainless steel foils. X-ray emission intensity increases as βΌ I 4.5 with laser intensity I on a target. High spectrally resolved x-ray emission from front and rear surfaces of 5 ΞΌm thickness stainless steel targets were obtained at the wavelength range 1.7-2.1 Γ
, for the first time in experiments at femtosecond petawatt laser facility J-KAREN-P. Total intensity of front x-ray spectra three times dominates to rear side spectra for maximum laser intensity I β 3.21021 W/cm2. Growth of x-ray emission is mostly determined by contribution of bremsstrahlung radiation that allowed estimating bulk electron plasma temperature for various magnitude of laser intensity on target
High order harmonics from relativistic electron spikes
A new regime of relativistic high-order harmonic generation is discovered [Phys. Rev. Lett. 108, 135004 (2012)]. Multi-terawatt relativistic-irradiance (>1018 W/cm2) femtosecond (~30-50 fs) lasers focused to underdense (fewΓ1019 cm-3) plasma formed in gas jet targets produce comb-like spectra with hundreds of even and odd harmonic orders reaching the photon energy of 360 eV, including the 'water window' spectral range. Harmonics are generated by either linearly or circularly polarized pulses from the J-KAREN (KPSI, JAEA) and Astra Gemini (CLF, RAL, UK) lasers. The photon number scalability has been demonstrated with a 120 TW laser producing 40 ΞΌJ/sr per harmonic at 120 eV. The experimental results are explained using particle-in-cell (PIC) simulations and catastrophe theory. A new mechanism of harmonic generation by sharp, structurally stable, oscillating electron spikes at the joint of boundaries of wake and bow waves excited by a laser pulse is introduced. In this paper detailed descriptions of the experiments, simulations and model are provided and new features are shown, including data obtained with a two-channel spectrograph, harmonic generation by circularly polarized laser pulses and angular distribution
Blood Content of Markers of Inflammation and Cytokines in Patients With Alcoholic Cardiomyopathy and Ischemic Heart Disease at Various Stages of Heart Failure
We conducted a comparative study of content proinflammatory cytokines, biomarkers of inflammatory process, biochemical indicators of congestive heart failure (CHF) and hemodynamic parameters in patients with alcoholic cardiomyopathy (ACMP) and ischemic heart disease (IHD) with various NYHA classes. We examined 62 men with ACMP (n = 45) and IHD (n = 17) and NYHA class III-IV CHF. Patients of both groups had lowered ejection fraction (EF), dilated cardiac chambers, and increased left ventricular (LV) myocardial mass index (MMI). Relative LV wall thickness was within normal limits but in the ACMP group it was significantly lower than in IHD group what corresponded to the eccentric type of myocardial hypertrophy. Higher NYHA class was associated with lower EF and larger end diastolic and end systolic LV dimensions. In ACMP it was also associated with larger dimension of the right ventricle while in IHD with substantially larger (by 30%) dimension of atria. Substantial amount of endotoxin found in blood plasma of patients with IHD corresponded to the conception of increased intestinal permeability of in CHF. Alcohol abuse was an aggravating factor of endotoxin transmission and its concentration in patients with ACMP was 3 times higher than in patients with IHD. Patients with ACMP had substantially elevated blood concentrations of interleukins (IL) 6, 8, 12, tumor necrosis factor alpha (TNF-alpha), and its soluble receptor s-TNF-R; they also had twofold elevation of C-reactive protein concentration. ACMP was associated with manifold rise of blood content of brain natriuretic peptide (BNP). Patients with IHD also had elevated blood concentrations of IL 6, 8 and 12 but their values were 1.5-2 times lower than ACMP group. Blood content of TNF-alpha and s-TNF-R in IHD group was within normal limits. Higher NYHA class in ACMP patients was associated with higher concentrations of IL 6 and 8, TNF-alpha, and BNP. In both groups of patients contents of IL-12, s-TNF-R, TGF-1 beta and factors of acute phase of inflammation did not reflect severity of CHF. Functional insufficiency of myocardium in IHD patients was best characterized by blood content of IL-6 while in ACMP patients of BNP