Search Results (5)

Theta Pinch is one of the promising methods for the generation of hot and dense plasma. In this paper, we describe the results of experimental research on a small-scale Theta Pinch created with Helium or Hydrogen plasmas. Different plasma diagnostics, namely, optical, microwave cut-off, laser interferometry, visible spectroscopy, Thomson scattering, and Laser-Induced Fluorescence were used to characterize the time- and space-resolved evolution of the plasma parameters, and the specific features of these diagnostic results obtained are discussed. The measured plasma density and the electron and ion temperature evolution, obtained by these various diagnostic tools, agree to a satisfactory level. These methods will be applied for studies of the parameters of the plasma in the device that is being developed by the nT-Tao company towards fusion energy. Full article

Objective: This study aimed to explore longitudinal relationships between neurophysiological biomarkers and upper limb motor function recovery in stroke patients, focusing on electroencephalography (EEG) and transcranial magnetic stimulation (TMS) metrics. Methods: This longitudinal cohort study analyzed neurophysiological, clinical, and demographic data from 102 stroke patients enrolled in the DEFINE cohort. We investigated the associations between baseline and post-intervention changes in the EEG theta/alpha ratio (TAR) and TMS metrics with upper limb motor functionality, assessed using the outcomes of five tests: the Fugl-Meyer Assessment (FMA), Handgrip Strength Test (HST), Pinch Strength Test (PST), Finger Tapping Test (FTT), and Nine-Hole Peg Test (9HPT). Results: Our multivariate models identified that a higher baseline TAR in the lesioned hemisphere was consistently associated with poorer motor outcomes across all five assessments. Conversely, a higher improvement in the TAR was positively associated with improvements in FMA and 9HPT. Additionally, an increased TMS motor-evoked potential (MEP) amplitude in the non-lesioned hemisphere correlated with greater FMA-diff, while a lower TMS Short Intracortical Inhibition (SICI) in the non-lesioned hemisphere was linked to better PST improvements. These findings suggest the potential of the TAR and TMS metrics as biomarkers for predicting motor recovery in stroke patients. Conclusion: Our findings highlight the significance of the TAR in the lesioned hemisphere as a predictor of motor function recovery post-stroke and also a potential signature for compensatory oscillations. The observed relationships between the TAR and motor improvements, as well as the associations with TMS metrics, underscore the potential of these neurophysiological measures in guiding personalized rehabilitation strategies for stroke patients. Full article

A capillary pulsed-discharge and a theta-pinch were used to record Kr spectra in the region of 330–4800 Å. A set of 168 transitions of these spectra were classified for the first time. We extended the analysis to twenty-five new energy levels belonging to 3s²3p²4d, 3s²3p²5d even configurations. We calculated weighted transition probabilities (gA) for all of the experimentally observed lines and lifetimes for new energy levels using a relativistic Hartree–Fock method, including core-polarization effects. Full article

An inductive pulsed plasma thruster (IPPT) operates by pulsing high current through an inductor, typically a coil of some type, producing an electromagnetic field that drives current in a plasma, accelerating it to high speed. The IPPT is electrodeless, with no direct electrical connection between the externally applied pulsed high-current circuit and the current conducted in the plasma. Several different configurations were proposed and tested, including those that produce a plasma consisting of an accelerating current sheet and those that use closed magnetic flux lines to help confine the plasma during acceleration. Specific impulses up to 7000 s and thrust efficiencies over 50% have been measured. The present state-of-the-art for IPPTs is reviewed, focusing on the operation, modeling techniques, and major subsystems found in various configurations. Following that review is documentation of IPPT technology advancement paths that were proposed or considered. Full article

In the gyrokinetic model and simulations, when the double-gyroaverage term incorporates the combining effect contributed by the finite Larmor radius, short scales of the perturbation, and steep gradient of the equilibrium profile, the low-order approximation of this term could generate unignorable error. This paper implements an interpolation algorithm to compute the double-gyroaverage term without low-order approximation to avoid this error. For a steep equilibrium density, the obvious difference between the density on the gyrocenter coordinate frame and the one on the particle coordinate frame should be accounted for in the quasi-neutrality equation. A Euler–Maclaurin-based quadrature integrating algorithm is developed to compute the quadrature integral for the distribution of the magnetic moment. The application of the interpolation algorithm to computing the double-gyroaverage term and to solving the quasi-neutrality equation is benchmarked by comparing the numerical results with the known analytical solutions. Finally, to take advantage of the interpolation solver clearer, the numerical comparison between the interpolation solver and a classical second order solver is carried out in a constant theta-pinch magnetic field configuration using SELALIB code. When the equilibrium profile is not steep and the perturbation only has the non-zero mode number along the parallel spatial dimension, the results computed by the two solvers match each other well. When the gradient of the equilibrium profile is steep, the interpolation solver provides a bigger driving effect for the ion-temperature-gradient modes, which possess large polar mode numbers. Full article