This paper is a sequel to the 1998 review paper “Scientific status of the Dense Plasma Focus” with 16 authors belonging to 16 nations, whose initiative led to the establishment of the International Center for Dense Magnetized Plasmas (ICDMP) in the year 2000. Its focus is on understanding the principal defining characteristic features of the plasma focus in the light of the developments that have taken place in the last 20 years, in terms of new facilities, diagnostics, models, and insights. Although it is too soon to proclaim with certainty what the plasma focus phenomenon is, the results available to date conclusively indicate what it is demonstrably not. The review looks at the experimental data, cross-correlated across multiple diagnostics and multiple devices, to delineate the contours of an emerging narrative that is fascinatingly different from the standard narrative, which has guided the consensus in the plasma focus community for several decades, without invalidating it. It raises a question mark over the Fundamental Premise of Controlled Fusion Research, namely, that any fusion reaction having the character of a beam-target process must necessarily be more inefficient than a thermonuclear process with a confined thermal plasma at a suitably high temperature. Open questions that need attention of researchers are highlighted. A future course of action is suggested that individual plasma focus laboratories could adopt in order to positively influence the future growth of research in this field, to the general benefit of not only the controlled fusion research community but also the world at large.

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A more generalized form of the non-Maxwellian distribution function, i.e., the AZ-distribution function is presented. Its fundamental properties are numerically observed by the variation of three parameters: α (rate of energetic particles on the shoulder), r (energetic particles on a broad shoulder), and q (superthermality on the tail of the velocity distribution curve of the plasma species). It has been observed that (i) the AZ- distribution function reduces to the (r,q)- distribution for α→0; (ii) the AZ- distribution function reduces to the q- distribution for α→0, and r→0; (iii) the  AZ-distribution reduces to Cairns-distribution function for r→0, and q→∞; (iv) the AZ-distribution reduces to Vasyliunas Cairns distribution for r→0, and q=κ+1; (v) the AZ-distribution reduces to kappa distribution for α→0, r→0, and q=κ+1; and (vi) finally, the AZ-distribution reduces to Maxwellian distribution   for α→0,r→0, and q→∞. The uses of this more generalized AZ- distribution function in various space plasmas are briefly discussed.

Carbon nanomaterials exhibit novel characteristics including enhanced thermal, electrical, mechanical, and biological properties. Nanodiamonds; first discovered in meteorites are found to be biocompatible, non-toxic and have distinct optical properties. Here we show that nanodiamonds with the size of <5 nm are formed directly from ethanol via 1025 nm femtosecond laser irradiation. The absorption of laser energy by ethanol increased non-linearly above 100 μJ accompanied by a white light continuum arises from fs laser filamentation. At laser energy higher than 300 μJ, emission spectra of C, O and H in the plasma were detected, indicating the dissociation of C2H5OH. Nucleation of the carbon species in the confined plasma within the laser filaments leads to the formation of nanodiamonds. The energy dependence and the roles of the nonlinear phenomenon to the formation of homogeneous nanodiamonds are discussed. This work brings new possibility for bottom-up nanomaterials synthesis based on nano and ultrafast laser physics.

Nonrepeatability in measured values of the static breakdown voltage Vs of uniform-field high-pressure gas-discharge gaps necessitates a large number of measurements to be made in order to construct meaningful V, distribution curves. An apparatus has been constructed which is capable of automatic measurement and recording of breakdown voltage data. This enables results to be obtained under more precise conditions than are possible using normal experimental techniques. The design and performance of this system are discussed with reference to some results obtained for pressurized nitrogen. Publ. 90 p 326 Chalmers I D and Thom J 1972 Proc. 2nd Znt. ConJ on Gas Discharges, London 1972: ZEE Conf. Pub[. 90 p 276 Figure 5 (pd = 1500 Torr cm)

Dust grain charging processes are presented in a non-Maxwellian dusty plasma following the Cairns-Tsallis (q, a)-distribution, whose constituents are the electrons, as well as the positive/negative ions and negatively charged dust grains. For this purpose, we have solved the current balance equation for a negatively charged dust grain to achieve an equilibrium state value (viz., q d ¼ constant) in the presence of Cairns-Tsallis (q, a)-distribution. In fact, the current balance equation becomes modified due to the Boltzmannian/streaming distributed negative ions. It is numerically found that the relevant plasma parameters, such as the spectral indexes q and a, the positive ion-toelectron temperature ratio, and the negative ion streaming speed (U 0) significantly affect the dust grain surface potential. It is also shown that in the limit q ! 1 the Cairns-Tsallis reduces to the Cairns distribution; for a ¼ 0 the Cairns-Tsallis distribution reduces to pure Tsallis distribution and the latter reduces to Maxwellian distribution for q ! 1 and a ¼ 0.

Ultra-high molecular weight polyethylene (UHMWPE) is widely used in artificial joints in the replacement of knee, hip and shoulder that has been impaired as a result of arthritis or other degenerative joint diseases. The UHMWPE made plastic cup is placed in the joint socket in contact with a metal or ceramic ball affixed to a metal stem. Effective reinforcement of multi-walled carbon nanotubes (MWCNTs) in UHMWPE results in improved mechanical and tribological properties. The hydrophobic nature of the nanocomposites surface results in lesser contact with biological fluids during the physiological interaction. In this project, we investigate the UHMWPE/MWCNTs nanocomposites reinforced with MWCNTs at different concentrations. The samples were treated with cold argon plasma at different exposure times. The water contact angles for 60 min plasma-treated nanocomposites with 0.0, 0.5, 1.0, 1.5, and 2.0 wt % MWCNTs were found to be 55.65˝, 52.51˝, 48.01˝, 43.72˝, and 37.18˝respectively. Increasing the treatment time of nanocomposites has shown transformation from a hydrophobic to a hydrophilic nature due to carboxyl groups being bonded on the surface for treated nanocomposites. Wear analysis was performed under dry, and also under biological lubrication, conditions of all treated samples. The wear factor of untreated pure UHMWPE sample was reduced by 68% and 80%, under dry and lubricated conditions, respectively, as compared to 2 wt % 60 min-treated sample. The kinetic friction co-efficient was also noted under both conditions. The hardness of nanocomposites increased with both MWCNTs loading and plasma treatment time. Similarly, the surface roughness of the nanocomposites was reduced.

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