Electrical conductivity of carbon plasma

Abstract

The electrical conductivity of carbon plasmas is measured in the range of densities from about 0.6 solid density down to about 0.05 solid density, and reported for values of internal energy ranging from 2 to 22 kJ/gm . Plasmas are formed by rapid electrical discharge through thin graphite fibers immersed in a water bath. The pressure in the expanding plasma column is determined by use of a hydrodynamic model to describe the effect on the water surround. It is found that at constant internal energy per unit mass U, conductivity sigma varies with specific volume v as sigma = v(-alpha), where alpha is about 1 for U < 6 kJ gm , and rises to about 1.5 for U = 22 kJ gm .

Imbalanced Feshbach-resonant Fermi gases

“…However, interesting physics also holds for systems in which LDA is violated. As discussed by DeSilva and Mueller [135], the early Rice experiments [56] showed axial density profiles (corresponding to the density, integrated over two directions, as a function of the coordinate z along the long axis of the cloud) that apparently violated the LDA. Indeed, the violation of the LDA can be directly seen in the data shown in Fig.…”

“…In recent years, there have been numerous theoretical investigations of the density profiles of trapped polarized fermion gases (see, e.g., Refs. [59,132,133,134,135,136,137,70,66,138,139,140,141,142,143]); here we shall focus on the predictions of the simplest method for handling the trapping potential, namely the local density approximation (LDA). Much like the WKB approximation, the LDA corresponds to using expressions for the bulk system, but with an effective local chemical potential µ(r) = µ − V T (r) in place of µ.…”

“…This issue was studied in more detail in Ref. [58], where the distorted shape (attributable to a nonzero surface tension [135] associated with the first-order transition and corresponding phase separation) of the paired inner core was confirmed, and the dependence of the aspect ratios of the minority and majority species fermionic clouds as a function of the imposed imbalance was measured. These later Rice experiments [58] also found a surprisingly large value of the in-trap upper critical polarization, P c2,trap ≈ 0.9.…”

The structure in warm dense carbon

“…Therefore, carbon in its many phases and forms has been investigated for a broad range of pressures and temperatures. In particular, the high pressure properties of carbon have attracted a lot of investigations in form of experiments using laser shocks [9][10][11][12][13][14], shocks generated using z-pinchs [15], or explosives [16,17]. These have been combined with VISAR or SOP diagnostics, and, especially in recent years, with x-ray scattering techniques [18][19][20][21][22][23][24][25][26][27][28].…”

Experiments and Simulations of Exploding Aluminum Wires: Validation of ALEGRA-MHD

“…The experimental setup consisted of a cylindrical Al chamber 15-cm deep and 30-cm in diameter. Details of the experimental apparatus have been reported in our previous publications (14)(15)(16). In the previous experiments, we assumed the length of the wire to be equal to the plate separation.…”