相关论文: Predicted thermal superluminescence in low-pressur…

We address the problem of overheating of electrons trapped on the liquid helium surface by cyclotron resonance excitation. Previous experiments, suggest that electrons can be heated to temperatures up to 1000K more than three order of…

High temperature radiating Air is produced experimentally by focusing a shock wave with the help of a spherically converging test section attached to a shock tube. The converging section concentrates the shock to a point with minimum…

Superflares on the solar type stars observed by \textit{Kepler} demonstrate the contrast in the optical continuum of the order 0.1--1 per cent. The mechanism of formation of this radiation is not firmly established. We consider a model…

We generalize the problem of the semi-gray model to cases in which a non-negligible fraction of the stellar radiation falls on the long-wavelength range, and/or that the planetary long-wavelength emission penetrates into the transparent…

We describe the characterization of a pulsed supersonic rare gas beam which is intended to serve as an ultracold neutral atom target for the production of an ultrashort ion pulse via femtosecond photoionization. The velocity distribution of…

We describe experiments where 2D atomic hydrogen gas is compressed thermally at a small "cold spot" on the surface of superfluid helium and detected directly with electron-spin resonance. We reach surface densities up to 5e12 1/cm^2 at…

This paper discusses a quantum optical heating mechanism which might play an important role in sonoluminescence experiments. We suggest that this mechanism occurs during the final stages of the bubble collapse phase and accompanies the…

Spitzer Space Telescope infrared observations indicate that several transiting extrasolar giant planets have thermal inversions in their upper atmospheres. Above a relative minimum, the temperature appears to increase with altitude. Such an…

We report on simulations of the formation of the first stars in the Universe, where we identify regions of hot atomic gas (fH2 < 10-6) at densities above 10-14 g/cc, heated to temperatures ranging between 3000 and 8000 K. Within this…

Sonoluminescence is the intriguing phenomenon of strong light flashes from tiny bubbles in a liquid. The bubbles are driven by an ultrasonic wave and need to be filled with noble gas atoms. Approximating the emitted light by blackbody…

Ultracold neutral plasmas are formed by photoionizing laser-cooled atoms near the ionization threshold. Through the application of atomic physics techniques and diagnostics, these experiments stretch the boundaries of traditional neutral…

A new method is proposed to produce population inversion on transitions involving the ground state of atoms. The method is realized experimentally with sodium atoms. Lasing at the frequency corresponding to the sodium D_2 line is achieved…

A new phenomenon of enhancing the relativistic transparency of overdense plasmas by the influence of hot-electron refluxing has been found via particle-in-cell simulations. When a p-polarized laser pulse, with intensity below the…

We propose a laser cooling mechanism that leads to a temperature significantly lower than the single-photon recoil limit, about $4\times 10^{-4}\,E_{r}$. This mechanism benefits from sharp and high-contrast spectra which are induced by…

Using a reliably measured intrinsic (i.e. corrected for absorption effects) present-day luminosity function of high-mass X-ray binaries (HMXBs) in the 0.25-2 keV energy band per unit star-formation rate, we estimate the preheating of the…

Recent theoretical predictions hint at an implementation of a superradiant laser based on narrow optical clock transitions by using a filtered thermal beam at high density. Corresponding numerical studies give encouraging results but the…

We employ semiclassical theoretical analysis to study laser cooling of free atoms using three-level cascade transitions, where the upper transition is much weaker than the lower one. This represents an alternate cooling scheme, particularly…

X-ray spectroscopy of cooling-flow clusters reveal an unexpected deficit of soft X-ray emission lines from gas at ~1/3 of the ambient plasma temperature, across a wide range of X-ray luminosities and virial temperatures. We propose excess…

Contemporary models of bounded plasmas assume that the target plasma electron temperature far exceeds the temperature of the cold electrons emitted from the target, T_emit. We show that when the sheath facing a collisional plasma becomes…

It is generally recognized that the interstellar medium has a vast range of densities and temperatures. While these two properties are usually anticorrelated with each other, there are nevertheless variations in their product, i.e., the…