Invariance concepts and scalability of two-temperature astrophysical radiating fluids

Abstract

In this work, we present a classification of laboratory astrophysics experiments. We introduce different invariance concepts in order to build scaling laws and to determine the astrophysical relevant of laboratory experiments. Finally we present an analysis of the two-temperature radiating fluid scalability.

Laboratory analogue of a supersonic accretion column in a binary star system

“…where Δ is a value depending on the dimensionless parameters of the system, u 1 is the incoming flow velocity to the shock front and is the cooling time 11 . The form of this equation is valid in a general sense for both optically thin and thick plasmas.…”

“…Indeed, the laboratory plasma does not radiate primarily by bremsstrahlung cooling, but instead by line emission. However, as the radiative processes modify the macroscopic structure of the flow, as also occurs at astrophysical scales, we can use the parametric similarity introduced by Falize et al 10 11 to relate the laboratory plasma to the astrophysical flows. Thus, the relation in equation (2) is applicable in the laboratory and astrophysics, and the results can be related to one another.…”

“…High power lasers, such as the Orion Laser Facility, Aldermaston (UK) 6 , can produce plasmas of sufficient density, velocity and temperature that are astrophysically relevant 7 8 . This is possible because of the hydrodynamic similarity that can be established between the laboratory and the astrophysical systems, which has been investigated in depth 9 10 11 12 13 14 15 , and, recently, also include the full combination of magnetohydrodynamics, radiation and quantum effects 16 .…”

The scalability of the accretion column in magnetic cataclysmic variables: the POLAR project

“…If such a goal is reached, the knowledge gained in the laboratory can be applied to similar astrophysical processes. Three main similarity concepts can be used in order to construct the desired scaling relations (Falize et al 2011b). Firstly the absolute similarity allows the construction of a scaled system, but the temperature and velocity regime that the scaling laws impose are out of reach for 1 kJ and 10 kJ laser facilities.…”

“…A theoretical study is in progress to constrain the nature of material which must be used in laboratory experiments in order to have a real scaled model. To these two scalability approaches we add a new similarity concept: the parametric similarity concept (Falize et al 2011b) which has been recently introduced. The latter benefits from the knowledge of a parametric analytical or semi-analytical solution which describes the system of interest.…”