Surface and structural darnage to plasma-facing components (PFCS) due to the frequent loss of plasma confinement remains a serious problem for the tokamak reaetor concept. The deposited plasma energy causes significant surface erosion, possible ~ structural failure, and frequent plasma contamination. vaporization, spa.llation, and liquid splatter of metallic Surface darnage consists of material...

In RFX-mod the feedback control on multiple magnetohydrodynamic modes allows to improve axysimmetry and to safely operate at high current. RFX-mod reliably operates at 1.5 MA, the highest current ever achieved on a Reversed Field Pinch (RFP). In these high current discharges magnetic topology spontaneously self-organizes in an ohmic helical symmetry, quasi single helicity state ( QSH), in which...

The outer region of the plasma column of a large, linear plasma device is rotated in a controlled fashion by biasing a section of the vacuum chamber wall positive with respect to the cathode Er 0 . The magnitude and temporal dependence of the observed cross-field current, produced when the bias voltage is applied, is consistent with ion current arising from ion-neutral collisions. Flow speeds i...

The strength and ductility of concrete improve under multi-axial compressive stress due to confinement effect. Some parameters are effective for considering the confinement in concrete and various stress-strain models were developed by different researchers. Longitudinal and transverse reinforcement steels can influence on confinement in reinforced concrete members. In this paper, various stres...

During immune surveillance and inflammation, leukocytes exit the vasculature through transient openings in the endothelium without causing plasma leakage. However, the exact mechanisms behind this intriguing phenomenon are still unknown. Here we report that maintenance of endothelial barrier integrity during leukocyte diapedesis requires local endothelial RhoA cycling. Endothelial RhoA depletio...

A computer model for an Electron Cyclotron Resonance Ion Source (ECRIS) plasma is under development that currently incorporates non-Maxwellian distribution functions, multiple atomic species, and ion confinement due to the ambipolar potential that arises from fast electrons. Atomic processes incorporated into the model include multiple ionization and multiple charge-exchange with rate coefficie...

On the Alcator C-Mod tokamak [Phys. Plasmas 1, 1511, (1994)], radial profiles of electron temperature (Te) and density (ne) are measured at the plasma edge with millimeter resolution Thomson scattering [Rev. Sci. Instrum. 72, 1107 (2001)]. Edge transport barriers in the high confinement regime (Hmode) exhibit Te, ne pedestals with typical widths of 2–6 mm, with the Te pedestal on average slight...

Current profile control is employed in the Madison Symmetric Torus @R. N. Dexter et al., Fusion Technol. 19, 131 ~1991!# reversed field pinch to reduce the magnetic fluctuations responsible for anomalous transport. An inductive poloidal electric-field pulse is applied in the sense to flatten the parallel current profile, reducing the dynamo fluctuation amplitude required to sustain the equilibr...