121538545
Interacting Ricci dark energy in scalar Gauss-Bonnet gravity
Abstract.This paper reports a study on the cosmological application of interacting Ricci Dark Energy (RDE) density in the scalar Gauss-Bonnet framework. The interacting holographic RDE model has been employed to obtain the equation of state (EoS) in a spatially flat universe. The main results of this paper are that the reconstructed potential of scalar Gauss-Bonnet gravity for the interacting RDE model decays with the evolution of the universe. However, it is an increasing function of the scalar field $ \phi$ . Both the strong and weak energy conditions are violated. A phantom-like behavior of the EoS parameter has been obtained. The effective EoS parameter $ \omega_{eff}$ stays below -1 but tends to -1 with the evolution of the universe. However, it cannot cross the phantom boundary. Finally, the interacting RDE model in Gauss-Bonnet gravity gives accelerated expansion of the universe.
119137152
Power Law and Logarithmic Ricci Dark Energy Models in Hořava-Lifshitz Cosmology
In this work, we studied the Power Law and the Logarithmic Entropy Corrected versions of the Ricci Dark Energy (RDE) model in a spatially non-flat universe and in the framework of Hořava-Lifshitz cosmology. For the two cases containing non-interacting and interacting RDE and Dark Matter (DM), we obtained the exact differential equation that determines the evolutionary form of the RDE energy density. Moreover, we obtained the expressions of the deceleration parameter q and, using a parametrization of the equation of state (EoS) parameter ωD given by the relation ωD(z) = ω0+ω1z, we derived the expressions of both ω0 and ω1. We interestingly found that the expression of ω0 is the same for both non-interacting and interacting case. The expression of ω1 for the interacting case has strong dependence from the interacting parameter b2. The parameters derived in this work are done in small redshift approximation and for low redshift expansion of the EoS parameter.
118578998
Interaction Between DBI-Essence and Other Dark Energies
The present work considers interaction between DBI-essence and other candidates of dark energies like modified Chaplygin gas, hessence, tachyonic field, and new agegraphic dark energy. The potentials of the fields have been reconstructed under interaction and their evolutions have been viewed against cosmic time t and scalar field φ. Equation of state parameters have also been obtained. The nature of potentials and the equation of state parameters of the dark energies have been found graphically in presence of interaction (both small and large interaction).
118740111
Correspondence Between Ricci and Other Dark Energies
Purpose of the present paper is to view the correspondence between Ricci and other dark energies. We have considered the Ricci dark energy in presence of dark matter in non-interacting situation. Subsequently, we have derived the pressure and energy density for Ricci dark energy. The equation of state parameter has been generated from these pressure and energy density. Next, we have considered the correspondence between Ricci and other dark energy models, namely tachyonic field, DBI-essence and new agegraphic dark energy without any interaction and investigated possible cosmological consequences.
62820584
Correspondence between f(G) gravity and holographic dark energy via power-law solution
In this paper, we discuss cosmological application of holographic Dark Energy (HDE) in the framework of f(G) modified gravity. For this purpose, we construct f(G) model with the inclusion of HDE and a well-known power law form of the scale factor a(t). The reconstructed f(G) is found to satisfy a sufficient condition for a realistic modified gravity model. We find quintessence behavior of effective equation of state (EoS) parameter ωDE through energy conditions in this context. Moreover, we observe that the squared speed of sound $v_{s}^{2}$ remains negative, which indicates the instability of HDE f(G) model.
119797547
New Agegraphic Dark Energy model in chameleon Brans-Dicke cosmology for different forms of the scale factor
In this work, we study the New Agegraphic Dark Energy (NADE) model (which contains the conformal time η as infrared cut-off) in the framework of Brans-Dicke cosmology with chameleon scalar field which is non-minimally coupled to the matter field. Considering interacting Dark Energy and Dark Matter (DM), we calculate some relevant cosmological parameters, i.e. the equation of state (EoS) parameter, the deceleration parameter q and the evolution of the energy density parameter $\varOmega_{D}'$ for different forms of scale factors, i.e. the power-law, the emergent, the intermediate and the logamediate ones, which leads to different expressions of η.
11133970
Transverse envelope dynamics of a 28.5-GeV electron beam in a long plasma.
The transverse dynamics of a 28.5-GeV electron beam propagating in a 1.4 m long, (0-2)x10(14) cm(-3) plasma are studied experimentally in the underdense or blowout regime. The transverse component of the wake field excited by the short electron bunch focuses the bunch, which experiences multiple betatron oscillations as the plasma density is increased. The spot-size variations are observed using optical transition radiation and Cherenkov radiation. In this regime, the behavior of the spot size as a function of the plasma density is well described by a simple beam-envelope model. Dynamic changes of the beam envelope are observed by time resolving the Cherenkov light.
121363140
Electron Injection in a Young Supernova & Evolution Towards a Supernova Remnant
The blast wave shock in SN 1993J has high sonic and Alfvenic Mach numbers ‐ ideal for ion plasma instabilities which generate plasma waves that energize electrons upon interaction. Plasma in the shock‐circumstellar interface is strongly magnetized, with the field energy density far exceeding that of the relativistic particles. This small “equipartition” for a young type IIb SN contrasts those of older Supernova remnants. Evolution of the radio spectrum of young supernovae can determine the change of the shock compression ratio as the SN ages and through comparison with models of particle acceleration coupled with hydrodynamics, can indicate the injection factor: the fraction of the total electrons that end up in the superthermal tail.
67820920
The LBL advanced light source
The LBL Advanced Light Source (ALS) will be a third generation synchrotron radiation facility. It is based on a low emittance 1--2 GeV electron storage ring (natural radial emittance <10 nm-rad), optimized to produce extremely bright beams of electromagnetic radiation (in the energy range from a few eV to around one keV) from insertion devices known as undulators. The storage ring is fed from an injection system consisting of a 50 MeV linac and a 1.5 GeV, 1 Hz, booster synchrotron, which can fill the ring to its normal operating current (400 mA, multibunch, or 7.6 mA, single bunch) in a few minutes. As well as high brightness (which is a consequence of the very small electron beam emittance in the storage ring), the design emphasizes: picosecond timestructure, laserlike coherence properties, narrow bandwidth, and long beam lifetimes. The more familiar continuous synchrotron radiation spectrum will be available from bending magnets and from wiggler magnets. This paper gives a general description of the ALS and discusses some of the significant design issues associated with the low emittance storage ring that is required for this new facility. 7 refs., 6 figs., 2 tabs.
124556579
Motivation and goals of ERL 2005
Various types of ERL sources are introduced, the relevant beam physics and accelerator technology issues noted, innovative areas of development identified and current and future goals of ERL research and development established.
121323860
Design concepts of a storage ring for a high power XUV free electron laser
Abstract We report on the study of a storage ring capable of sustaining an electron beam of the quality required for a high-gain free electron laser in the vacuum ultraviolet and X-ray region. We describe a method for the optimization of the design of the storage ring where several competing and often conflicting requirements come into play. We present an example design of a ring that satisfies the required conditions of beam quality and is able to produce coherent radiation at 400 A with tens of megawatts of peak power.