[en] The plasma potential is measured in TEXT-Upgrade tokamak by injection and detection of high energy heavy ions (thallium, and cesium with a single charge) using a 2 MeV accelerator and a parallel plate energy analyzer. The change in beam energy, as it crosses the plasma, gives the local plasma potential at the measurement volume. Recent results of high energy beam operations are presented

[en] The paper presents in foil form a mirror beam plasma neutron source for fusion reactor materials development and blanket component testing

[en] The flow and fluctuation measurements in a simple magnetized current less toroidal plasma have been conducted. The measured plasma parameter profiles are observed to be accompanied by large fluctuations. The existence of large fluctuations and filling of plasma in the entire radial domain are observed to be closely related to each other. The ExB drift velocities calculated from the gradient of measured mean plasma potential profile have shown significant deviation from the net flow velocity measurements. Interestingly, it is observed that the measured fluctuation driven flow velocity, which is opposite in direction to the mean field driven flow, partially accounts for the observed difference between the net flow and the mean electric field driven flow.

[en] A general method for the determination of the uncertainty of a physical quantity measured during an experiment is presented. This procedure is described step-by-step so it can be applied to any measurement and experiment available for undergraduate and graduate students, from the simplest to the most complex. The method is then applied to a classic measurement of plasma physics: the plasma potential determination using an emissive probe. This kind of experiment is routinely performed in plasma physics laboratories and may be realized by graduate students. The emissive probe diagnostic relies on a data analysis method called the inflection point. This method follows an indirect procedure on which the step-by-step uncertainty calculation strategy presented in the first part of the article is presented. (paper)

No abstract available

[en] The paper presents in foil form a mirror based source of fusion neutrons aimed for fusion material testing

[en] The paper presents in foil form a mirror-type plasma neutron source based on the GDT (Gas Dynamic Trap) concept

No abstract available

[en] The temporal evolution of the plasma potential, V_p, in a pulsed dc magnetron plasma has been determined using the emissive probe technique. The discharge was operated in the 'asymmetric bi-polar' mode, in which the discharge voltage changes polarity during part of the pulse cycle. The probe measurements, with a time-resolution of 20 ns or better, were made along a line above the racetrack, normal to the plane of the cathode target, for a fixed frequency (100 kHz), duty cycle (50%), argon pressure (0.74 Pa) and discharge power (583 W). At all the measured positions, V_p was found to respond to the large and rapid changes in the cathode voltage, V_d, during the different phases of the pulse cycle, with V_p always more positive than V_d. At a typical substrate position (>80 mm from the target), V_p remains a few volts above the most positive surface in the discharge at all times. In the 'on' phase of the pulse, the measurements show a significant axial electric field is generated in the plasma, with the plasma potential dropping by a total of about 30 V over a distance of 70 mm, from the bulk plasma to a position close to the beginning of the cathode fall. This is consistent with measurements made in the dc magnetron. During the stable 'reverse' phase of the discharge, for distances greater than 18 mm from the target, the axial electric field is found to collapse, with V_p elevated uniformly to about 3 V above V_d. Between the target and this field-free region an ion sheath forms, and the current flowing to the target is still an ion current in this 'reverse' period. During the initial 200 ns of the voltage 'overshoot' phase (between 'on' and 'reverse' phases), V_d reached a potential of +290 V; however, close to the target, V_p was found to attain a much higher value, namely +378 V. Along the line of measurement, the axial electric field reverses in direction in this phase, and an electron current of up to 9 A flows to the target. The spatial and temporal measurements of V_p presented here confirm a simple picture of the evolution of V_p, predicted from previously made time-resolved mass spectroscopic measurements of the ionic component in the pulsed magnetron. This paper describes the development and characteristics of the emissive probe technique for such fast measurements, together with implications for the form of the measured transient potential profiles on the operation of the magnetron discharge. In particular, it addresses the charged particle drifts and the potential for sputtering of the walls and the anode by ion impact

[en] The thermodynamic quantities in a dusty plasma gas display a strong nonlinear dependence on the grain charge. Due to the presence of charge correlations, relations between various quantities are very different than in an ordinary plasma. The entropy in such a plasma behaves very differently than in an electron-ion plasma. The origin of such a difference is traced to the nonlinear dust potential. The dependence of the specific heat on the grain charge also displays strong grain charge dependence. Further, it is demonstrated that the charge fluctuation is the prime source of irreversible entropy generation in a dusty plasma environment