Measurement of derivative of ion temperature using high spatial resolution charge exchange spectroscopy with space modulation optics

A new technique to measure the first and second derivatives of the ion temperature profile has been developed by using a charge exchange spectroscopy system with space modulation optics. The space observed is scanned up to ±3 cm with a cosine wave modulation frequency up to 30 Hz by shifting the object lens in front of the optical fiber bundle by 0.5 mm with a piezoelement. The first and second derivatives of ion temperature are derived from the modulation component of the ion temperature measured by using Fourier series expansion

Observation of charge-exchange spectra on C6+ +H in low-energy collision

The extreme ultraviolet spectra of C VI have been studied for a Neutral Beam Injection (NBI) plasmas in Large Helical Device (LHD). A strong distortion in the population distribution over the excited levels was observed and we conclude that is caused by charge-exchange recombining (CXR) processes between C^6+ ion and recycling neutral hydrogen. Spatially resolved measurements show that the C^6+-H CXR processes take place in the plasma peripheral region in LHD. We have taken a CXR pan of C VI 1s-4p line using the result of a calculation code

Bifurcation Phenomena of a Magnetic Island at a Rational Surface in a Magnetic-Shear Control Experiment

Three states of a magnetic island are observed when the magnetic shear at the rational surface is modified using inductive current associated with the neutral beam current drive in the Large Helical Device. One state is the healed magnetic island with a zero island width. The second state is the saturated magnetic island with partial flattening of the T_e profile. The third state is characterized by the global flattening of the T_e profile in the core region. As the plasma assumes each of the three states consecutively through a bifurcation process a clear hysteresis in the relation between the size of the magnetic island and the magnetic shear is observed

Extraction of a strongly focusing He + beam from three-stage concave electrodes for alpha particle measurement system in ITER

A strongly focusing He + ion beam source equipped with concave multi-aperture electrodes was developed for production of He - through a charge exchange cell. The beam was extracted at a voltage less than 20 kV from 301 apertures distributed in an area of 100 mm , and focused at 750 mm distance. The beam current and the beam size of 2 A and 20 mm in diameter, respectively, were achieved with an arc power less than 10 kW. The optimum perveance was obtained at 0.02 AkV 1.5 at the beam energy less than 20 keV which is suitable for the conversion to He - in an alkali vapor cell

Protective effect of 17β-estradiol on ischemic acute renal failure through the PI3K/Akt/eNOS pathway

Estrogens attenuate renal injury induced by ischemia/reperfusion (I/R), an effect that is related to nitric oxide production in the post-ischemic kidney. The compound 17β-estradiol (E2-β) acting via estrogen receptors (ERs) is known to activate endothelial nitric oxide synthase (eNOS) through the phosphatidylinositol-3 kinase (PI3K)/Akt pathway. We determined if this pathway contributes to the renoprotective effect of E2-β in the uninephrectomized ischemia reperfusion rat model of acute renal injury. Treatment with E2-β suppressed the I/R-induced increases in blood urea nitrogen, plasma creatinine, urine flow, and fractional excretion of sodium while augmenting creatinine clearance, renal blood flow, and urine osmolality, indicating attenuation of renal injury. Phosphorylation of Akt and eNOS protein was significantly increased 30–60 min after reperfusion in estradiol-treated compared to vehicle-treated rats. The protective effects of E2-β and protein phosphorylation were reversed by the PI3K inhibitor wortmannin or the ER antagonist tamoxifen. Furthermore, the E2-β-induced renoprotective effects were not seen in eNOS knockout mice with renal injury. We conclude that the E2-β-induced renoprotective effect is due to activation of the PI3K/Akt pathway followed by increased eNOS phosphorylation in the post-ischemic kidney