Query: Radiation energy

title: Radiation Energy and Beam Limitation
abstract: In our whole discussion of image formation and optical instruments, the details of lens fabrication and ray diagrams have not been emphasized; instead, we have used the limiting boundaries of light beams as an explanatory principle. This decisive point will also lead us to an understanding of energy transport by radiation, whether or not it is accompanied by image formation.

title: Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic Ray Energy.
abstract: We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8+ 0.7(stat) 6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic ray energy. A comparison with predictions from state of the art first principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic ray radio detector against the well established energy scale of the Pierre Auger Observatory.

title: Simulation of Radiation Energy Release in Air Showers
abstract: A simulation study of the energy released by extensive air showers in the form of MHz radiation is performed using the CoREAS simulation code. We develop an efficient method to extract this radiation energy from air shower simulations. We determine the longitudinal profile of the radiation energy release and compare it to the longitudinal profile of the energy deposit by the electromagnetic component of the air shower. We find that the radiation energy corrected for the geometric dependence of the geomagnetic emission scales quadratically with the energy in the electromagnetic component of the air shower with a second order dependence on the atmospheric density at the position of the maximum shower development $X_\mathrm{max} In a measurement where $X_\mathrm{max} is not accessible, this second order dependence can be approximated using the zenith angle of the incoming direction of the air shower with only a minor loss in accuracy. Our method results in an intrinsic uncertainty of 4% in the determination of the energy in the electromagnetic air shower component, which is well below current experimental uncertainties.

title: High efficiency room temperature ZnSe:Fe2+ laser with a high pulsed radiation energy
abstract: Characteristics of a ZnSe:Fe2+ laser operating at room temperature of active polycrystalline elements with large transversal dimensions are investigated. The active elements had a shape of plates with diameters D 25 63 mm and width of ~4 mm, doped from two sides with iron ions by the diffusion method. The plates were doped in the process of hot isostatic pressing at an argon pressure of 100 MPa and temperature of 1250 degC for 75 151 h. The laser was pumped by a non chain electrodischarge HF laser operated in a single pulse mode. The employment of active elements with greater transversal dimensions resulted in a suppressed transversal parasitic oscillation at large diameters of the pumping spot. The generation energy of 1.43 J with the slope efficiency eslope 53 and the total efficiency with respect to the energy absorbed in an active element eabs 48 was obtained on the sample of diameter D 63 mm.

title: Thermal radiation energy on squeezed MHD flow of Cu, Al2O3 and CNTs nanofluid over a sensor surface
abstract: The squeezed MHD flow of water, ethylene glycol and engine oil based metallic nanoparticles over a sensor surface in the presence of thermal radiation energy have been investigated. The physical significance of the problem is water, ethylene glycol and engine oil based on the geometry and the interaction of copper (Cu) alumina (Al2O3) and carbon nanotubes (SWCNTs and MWCNTs) The governing partial differential equations of momentum and energy are transformed to similarity equations (ODEs) for certain families of the controlling parameters. The numerical and analytical solutions of the resulting ODEs are solved using fourth or fifth order Fehlberg method with shooting technique and optimal homotopy asymptotic method (OHAM) and it is also found that there is no significance difference between them. It is investigated that in squeezing flow phenomena, SWCNTs engine oil in the presence of thermal radiation energy gives approximately more than 30% enhancement in the heat transfer as compared to the water based SWCNTs and MWCNTs.

title: On the thermodynamic origin of the initial radiation energy density in warm inflation
abstract: In warm inflation scenarios, radiation always exists, so that the radiation energy density is also assumed to be finite when inflation starts. To find out the origin of the non vanishing initial radiation energy density, we revisit thermodynamic analysis for a warm inflation model and then derive an effective Stefan Boltzmann law which is commensurate with the temperature dependent effective potential by taking into account the non vanishing trace of the total energy momentum tensors. The effective Stefan Boltzmann law shows that the zero energy density for radiation at the Grand Unification epoch increases until the inflation starts and it becomes eventually finite at the initial stage of warm inflation. By using the above effective Stefan Boltzmann law, we also study the cosmological scalar perturbation, and obtain the sufficient radiation energy density in order for GUT baryogenesis at the end of inflation.

title: High frequency spectral distribution of the equilibrium radiation energy in a plasma
abstract: We establish that the difference of the spectral distribution of the equilibrium radiation energy in matter from the Planck formula in the high frequency range is determined by the imaginary part of the transverse dielectric permittivity of the matter. Based on this, we show that in a rarified high temperature fully ionized nonrelativistic plasma, the high frequency spectral distribution of the equilibrium radiation energy differs essentially from the Planck formula because of the power law character of the decrease in the frequency, which is due to the presence of matter.

title: Applications of Radiation Energy Transfer

title: Increasing the radiation energy of ZnSe??Fe2+ laser at room temperature
abstract: Characteristics of the laser on a polycrystalline ZnSe??Fe2+ sample pumped by the radiation of a non chain electro discharge HF laser at room temperature are investigated. The radiation spot of the HF laser on a surface of an active element had an elliptical shape with the axes a b 2.8??3.2 8.25??9.5?mm. A maximal generation energy E 192?mJ was obtained at the efficiency with respect to the energy absorbed in the sample ?abs 23% at the dimensions of the pumping spot a b 6.8??7.5?mm. In this case, a maximal slope efficiency with respect to the absorbed energy was ?sl 29% At the spot dimensions a b 2.8??3.2?mm the slope efficiency was ?sl 34% Possibilities of a further increase of the generation energy of a ZnSe??Fe2+ laser pumped by radiation of the HF laser at room temperature are discussed.

title: Radiation Energy Balance Method for Calculating the Time Evolution of Type Ia Supernovae During the Post Explosion Phase
abstract: A new method is presented for calculating the time evolution of spherically symmetric Type Ia Supernova in the post explosion phase, enabling light curves and spectra to be simulated in a physically self consistent way. The commonly exploited radiative equilibrium, that is in essence a /gas energy balance/ condition, is unsuitable for this purpose for important physical and numerical reasons. Firstly, the RE depends on the heating and cooling rates of the gas by the radiation field, two quantities that almost completely cancel and are very difficult to calculate accurately. Secondly, the internal energy of the gas is only a tiny fraction of the total energy in the system (the vast majority of the energy resides in the radiation field) so that the vast majority of the energy is neglected in solving for the energy balance. The method presented in this paper, based on the /radiation energy balance/ addresses the bulk of the energy, does not depend on the heating/cooling rates, guarantees an accurate run of the bolometric luminosity over time while bringing the gas temperatures into consistence with the radiation field. We have implemented the method in the stellar atmosphere code PHOENIX and applied it to the classical W7 model. The results illustrate the importance of each of the four physical contributions to the energy balance as a function of time. The simulated spectra and light curves for W7 show good resemblance to the observations, which demonstrates what can be done using PHOENIX with the REB method.