Plasma space-dependent plasmas

B. The Consistent Balance Equations in Space-Dependent Plasmas. 63... 

Furthermore, the detailed procedure ultimately used to determine the velocity distribution sensitively depends on the type of plasma and is quite different when studying the electron kinetics in steady-state, time-dependent, or space-dependent plasmas. 

Equations (12), simplified by the assumption of isotropic scattering in exciting and dissociating collisions, represent the basic equations for studying many quite different problems in electron kinetics. In particular, the additional simplification to steady-state, purely time-dependent, or purely space-dependent plasma conditions allows a detailed microphysical analysis of various electron kinetic problems related to each of these plasma conditions. 

When specifying the kinetic treatment based on the two-term approximation to purely space-dependent plasmas with isotropic scattering in the important... 

In purely space-dependent plasmas, the consistent particle, power, and momentum balance equations of the electrons, Eqs. (31) to (33), have the simplified representation (Sigeneger and Winkler, 1997a Sigeneger and Winkler, 1996)... 

By the preceding representations, an attempt has been made to give, on the basis of the electron Boltzmann equation, an introduction to the kinetic treatment of the electron component in steady-state, time-dependent, and space-dependent plasmas and to illustrate by selected examples the large variety of electron kinetics in anisothermal weakly ionized plasmas. 

The metabolic control of methionine metabolism is complex and involves, for example, changes of enzyme levels in particular tissues, mechanisms linked to the kinetic properties of the various enzymes and their interaction with metabolic effectors [6, 7]. A particularly important metabolic effector is AdoMet. This inhibits the low Km isoenzymes of MAT, and MTHF reductase, inactivates betaine methyltransferase, but activates MAT III (the high-Km isoenzyme) and cystathionine /1-synthase. Therefore, high methionine intake and thus higher AdoMet levels favour trans-sulphuration, and when levels are low methionine is conserved. AdoHcy potently inhibits AdoMet-dependent methyltransferases and both Hey remethylating enzymes. Another important control mechanism is the export of Hey from cells into the extracellular space and plasma, which occurs as soon as intracellular levels increase [8]. 

As a consequence, for different plasma conditions—for instance, steady-state, time-dependent, or space-dependent problems—different solution approaches and numerical techniques have been developed and applied. In addition, the specific structure of the electric field acting upon the electrons is of particular importance for the establishment of a special symmetry in the velocity distribution and thus for a specific simplification of the solution approach. 

In contrast to the situation in plasmas in steady state or in time-dependent plasmas, the electron density n z) in space-dependent plasmas always depends on the z coordinate, and this happens already if only conservative inelastic collisions are considered. As an immediate consequence, it no longer makes sense to separate the density from the isotropic and anisotropic distribution of the electrons. 

A quite different situation with respect to the spatial behavior of the electron component arises if the inhomogeneity of the plasma is caused by a plasma confinement. The electron kinetics established in the radial direction of the positive column of dc glow discharges, which usually operates in a cylindrical discharge tube with an isolated wall, presents a representative example (Kortsha-gen, 1995 Uhrlandt and Winkler, 1996 Pfau et al, 1996 Alves et al, 1997) of such a condition. From the point of the electron kinetics, this space-dependent problem is somewhat more complex than those considered above. 

SODIUM-DEPENDENT SYMPORTERS IN THE PLASMA MEMBRANES CLEAR GLUTAMATE FROM THE EXTRACELLULAR SPACE 286... 

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