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Raman amplification of a short laser pulse off a long laser beam has been demonstrated successfully for moderate probe intensities ($\sim 10^{16}$ W/cm$^2$) and widths ($\sim 50$ micron). However, truly competitive intensities can only be…

An intense X wave propagating perpendicularly to dc magnetic field is unstable with respect to a parametric decay into an electron Bernstein wave and a lower-hybrid wave. A modified theory of this effect is proposed that extends to the…

Plasma Physics · Physics 2017-04-26 I. Y. Dodin , A. V. Arefiev

Laser beams carrying orbital angular momentum (OAM) provide an additional degree of freedom and have found wide applications ranging from optical communications and optical manipulation to quantum information. The efficient generation and…

X-ray spectroscopy is a sensitive probe of stellar winds. X-rays originate from optically thin shock-heated plasma deep inside the wind and propagate outwards throughout absorbing cool material. Recent analyses of the line ratios from…

Astrophysics · Physics 2008-06-17 L. M. Oskinova , W. -R. Hamann , A. Feldmeier

Light amplification towards extremely high power in the infrared regime remains a significant challenge due to the lack of suitable gain media. Here we propose a new scheme to amplify a laser pulse with tunable wavelengths towards extremely…

Plasma Physics · Physics 2025-02-13 Zhi-Yu Lei , Zheng-Ming Sheng , Su-Ming Weng , Min Chen , Jie Zhang

A standard version of a kinetic instability for the generation of Langmuir waves by a beam of electrons is adapted to describe the analogous instability due to a beam of neutrinos. The interaction between a Langmuir wave and a neutrino is…

Astrophysics · Physics 2009-10-30 S. J. Hardy , D. B. Melrose

The propagation of Langmuir waves in plasmas is known to be sensitive to density fluctuations. Such fluctuations may lead to the coexistence of wave pairs that have almost opposite wave-numbers in the vicinity of their reflection points.…

Space Physics · Physics 2011-07-25 V. V. Krasnoselskikh , T. Dudok de Wit , S. D. Bale

We report new experiments on polarization squeezing using ultrashort photonic pulses in a single pass of a birefringent fiber. We measure what is to our knowledge a record squeezing of -6.8 +/- 0.3 dB in optical fibers which when corrected…

Radiative transfer equations are derived and solved for the stimulated Raman scattering of water maser lines in the astrophysical plasmas with electron density of about 10^6 - 10^7 cm-3. In stimulated Raman scattering, the energy of water…

Astrophysics · Physics 2009-10-31 R. T. Gangadhara , Shuji Deguchi , H. Lesch

A compact low-energy and high-intensity X-ray source for radiation biology applications is presented. A laser-induced plasma moves inside a 30 kV diode and produces a beam of 10$^{14}$ electrons at the anode location. An aluminum foil…

Applied Physics · Physics 2021-02-02 F. Gobet , P. Barberet , L. Courtois , G. Deves , J. Gardelle , S. Leblanc , L. Plawinski , H. Seznec

Active energy compression scheme is presently being investigated for future laser-plasma accelerators. This method enables generating laser-plasma accelerator electron beams with a small, $\sim 10^{-5}$, relative slice energy spread. When…

We calculate spectra of radiation produced by a relativistic particle in the presence of one-dimensional Langmuir turbulence which might be generated by a streaming instability in the plasma, in particular, in the shock front or at the…

Astrophysics · Physics 2009-06-23 Gregory D. Fleishman , Igor N. Toptygin

ROSAT observations indicate that approximately half of all nearby groups of galaxies contain spatially extended X-ray emission. The radial extent of the X-ray emission is typically 50-500 kpc or approximately 10-50% of the virial radius of…

Astrophysics · Physics 2009-10-31 John S. Mulchaey

Quadrature amplitude modulation (QAM) and a complementary representation of a causal waveform have been used to develop a sidelobe-free pulse-compression technique. Envelopes of radio-frequency (RF) pulses under study include both unimodal…

Signal Processing · Electrical Eng. & Systems 2021-10-20 W. J. Szajnowski

A method for the controlled generation of intense high frequency electromagnetic fields by a breaking Langmuir wave (relativistic flying mirrors) in a gradually inhomogeneous plasma is proposed. The wave breaking threshold depends on the…

X-rays have widespread applications in science and industry, but developing a simple, compact, and high-quality X-ray source remains a challenge. Our collaboration has explored the possible use of channeling radiation driven by a 50 MeV…

Accelerator Physics · Physics 2016-12-23 A. Halavanau , D. Mihalcea , D. Broemmelsiek , D. Edstrom , T. Sen , A. Romanov , J. Ruan , V. Shiltsev , P. Kobak , W. Rush , J. Hyun

Of particular interest for radio and hard X-ray diagnostics of accelerated electrons during solar flares is the understanding of the basic non-linear mechanisms regulating the relaxation of electron beams propagating in turbulent plasmas.…

Space Physics · Physics 2015-03-06 Nicolas H. Bian , Eduard P. Kontar , Heather Ratcliffe

We study the properties of the diffuse X-ray background by using the results of a cosmological hydrodynamical simulation of the concordance LambdaCDM model. The simulation follows gravitational and gas dynamics and includes a treatment of…

Astrophysics · Physics 2009-11-13 M. Roncarelli , L. Moscardini , P. Tozzi , S. Borgani , L. M. Cheng , A. Diaferio , K. Dolag , G. Murante

In the presence of an intense ion acoustic wave, the energy-momentum dispersion relation of plasmons is strongly modified to exhibit a band gap structure. The intensity of an ion acoustic wave might be measured from the band gap width. The…

Plasma Physics · Physics 2010-04-27 S. Son , S. Ku