Determination of equilibrium density distribution and temperature of a pure electron plasma confined in a Penning trap

2006 ◽  
Vol 13 (11) ◽  
pp. 112109 ◽  
Author(s):  
J. Aoki ◽  
Y. Kiwamoto ◽  
Y. Kawai
Keyword(s):  
Density Distribution ◽  
Penning Trap ◽  
Electron Plasma ◽  
Equilibrium Density

scholarly journals Penning-trap Q-value determination of the Ga71(ν,e−)Ge71 reaction using threshold charge breeding of on-line produced isotopes

2013 ◽  
Vol 722 (4-5) ◽  
pp. 233-237 ◽  
Author(s):  
D. Frekers ◽  
M.C. Simon ◽  
C. Andreoiu ◽  
J.C. Bale ◽  
M. Brodeur ◽  
...  
Keyword(s):  
Penning Trap ◽  
Q Value ◽  
Charge Breeding ◽  
On Line ◽  
Value Determination

Suppression of turbulence in the drift-resistive plasma where zonal flow changes direction

2020 ◽  
Vol 86 (3) ◽  
Author(s):  
Chang-Bae Kim
Keyword(s):  
Electric Potential ◽  
Zonal Flow ◽  
Equilibrium Density ◽  
Turbulence Level ◽  
Edge Region ◽  
Transport Barrier ◽  
Large Gradient ◽  
Resistive Plasma ◽  
Flow Changes

The edge region of quasi-adiabatic plasma is pedagogically simulated by the dynamics between the electric potential $\unicode[STIX]{x1D711}$ and the electron density $n$ whose equilibrium density gradient is negative and held fixed. The zonal flow (ZF) $V$ is either enforced sinusoidally or generated self-consistently from the turbulence. Cross-phase $\unicode[STIX]{x1D6FF}$ between $\unicode[STIX]{x1D711}$ and $n$ , which is important in the determination of the turbulence level and the transport, is strongly influenced by the ZF. In the region near $V=0$ , $\unicode[STIX]{x1D6FF}$ becomes negative due to the large gradient of the ZF. It is found that the instabilities are quenched there, and the fluctuations decay. The ZF thus works as a transport barrier in the region where the ZF changes direction with large gradient.

scholarly journals Equilibrium Wigner Function for Fermions and Bosons in the Case of a General Energy Dispersion Relation

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1023
Author(s):  
Vito Dario Camiola ◽  
Liliana Luca ◽  
Vittorio Romano
Keyword(s):  
Wigner Function ◽  
Natural Generalization ◽  
Bloch Equation ◽  
Equilibrium Density ◽  
Diagonal Form ◽  
Energy Dispersion ◽  
Unitary Evolution ◽  
Von Neumann ◽  
General Energy

The approach based on the Wigner function is considered as a viable model of quantum transport which allows, in analogy with the semiclassical Boltzmann equation, to restore a description in the phase-space. A crucial point is the determination of the Wigner function at the equilibrium which stems from the equilibrium density function. The latter is obtained by a constrained maximization of the entropy whose formulation in a quantum context is a controversial issue. The standard expression due to Von Neumann, although it looks a natural generalization of the classical Boltzmann one, presents two important drawbacks: it is conserved under unitary evolution time operators, and therefore cannot take into account irreversibility; it does not include neither the Bose nor the Fermi statistics. Recently a diagonal form of the quantum entropy, which incorporates also the correct statistics, has been proposed in Snoke et al. (2012) and Polkovnikov (2011). Here, by adopting such a form of entropy, with an approach based on the Bloch equation, the general condition that must be satisfied by the equilibrium Wigner function is obtained for general energy dispersion relations, both for fermions and bosons. Exact solutions are found in particular cases. They represent a modulation of the solution in the non degenerate situation.

scholarly journals High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP–oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

IUCrJ ◽  
2016 ◽  
Vol 3 (2) ◽  
pp. 115-126 ◽  
Author(s):  
E. I. Howard ◽  
B. Guillot ◽  
M. P. Blakeley ◽  
M. Haertlein ◽  
M. Moulin ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
High Resolution ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Room Temperature ◽  
Water Molecules ◽  
X Ray

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H...H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.

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