Plasma density

Figure 2. Plasma density (particles/m ) against energy for various plasma systems.

Author has studied the phenomenon in detail, and published the results [3-5] that the observable possibility is appreciable, while Lawson condition is not satisfied. In order to realize the nuclear emission, both the plasma temperature (T0) and the density of D ions (nD) should be large enough to satisfy the required conditions. The density rto is determined by plasma density, which depends upon the vapor pressure in the initial bubble. 

In the case of nonrelativistic laser intensity, linear theory does not allow propagation in overdense plasmas, namely when to 1 < iop(. = e(An/rn,.) 2n,J 2. In the extreme case of ultra-relativistic laser intensity (ao 2> 1), the cutoff frequency for propagation drops from u pe down to wpe/(l Tag)1/4 [11], where ao = eA/mec is the dimensionless amplitude of the laser field. Then, in order for the propagation to occur at plasma density appreciably higher than the ordinary critical density, ao 2> 1 is needed. This is also the case of overdense thin plasma layers (as proved by simulation [12]) whose thickness exceeds the skin penetration depth of the e.m. wave. Theoretical background and basic... 

N.W. Schmidt, T.S. Totushek, W.A. Kimes, D.R. Callender, and J.R. Doyle, Effects of substrate temperature and near-substrate plasma density on the properties of d.c. magnetron sputtered aluminum-doped zinc oxide, J. Appl. Phys., 94 5514-5521 (2003). 

Fig. 4. The carbon atom yield (squares and left hand axis) reported by Jurgensen and Rammelsberg [34], is compared to the etching rate at constant plasma density (triangles and right hand axis) reported by Paraszczak et al. [32]. The line is a linear least squares fit to the Jurgensen s [34] results.

The ionization potential appears to reduce sharply towards zero with decrease of the ion sphere radius indicating the effect of increased plasma coupling strength. Table 1 gives the energy levels of hydrogen-like Ne in a plasma environment for different plasma densities. 

The calculated results for Sil et al. [174] agree well with those of Skupski [162] and Nguyen et al. [154], For hydrogen-like Al the transition energy vs plasma density [176] is plotted in Figure 13. 

Figure 16 Plot of the scaled fine structure correction for the ground state of hydrogen-like ions for different plasma densities using Ion Sphere model. Reprinted with permission from [180]...

In order to achieve an overall positive energy balance the D-T plasma has to be heated to the ignition temperature of 5 keV and confined for a sufficiently long time4). Energy breakeven is usually expressed in terms of the Lawson criterion which states that the product of the plasma density, n, and the energy confinement time re has to exceed a critical value which is a function of the plasma temperature4 8). 

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