Search results for "PLASMA"

Non-Thermal Fusion Burning Plasma Regimes

The Ignitor project is aimed at approaching ignition conditions in Deuterium-Tritium plasmas in order to investigate the issues related to the kind of characteristics of these plasmas, following the line of compact high field opened with the Alcator and Frascati Torus programs, which were capable of producing high density plasma regimes with record confinement properties combined with high degrees of plasma purity. We present a theoretical model describing the emergence of tridimensional structures in magnetically confined plasmas which can significantly change the conditions under which meaningful fusion burn conditions can be reached. These structures can be said to consist of "captive ba…

Effects of magnetic configuration on hot electrons in a minimum-B ECR plasma

2020

To investigate the hot electron population and the appearance of kinetic instabilities in highly charged electron cyclotron resonance ion source (ECRIS), the axially emitted bremsstrahlung spectra and microwave bursts emitted from ECRIS plasma were synchronously measured on SECRAL-II (Superconducting ECR ion source with Advanced design in Lanzhou No. II) ion source with various magnetic field configurations. The experimental results show that when the ratio of the minimum field to the resonance field (i.e. Bmin/Becr) is less than ~0.8, the bremsstrahlung spectral temperature Ts increases linearly with the Bmin/Becr–ratio when the injection, extraction and radial mirror fields are kept const…

Aluminum tri-isopropoxide as an alternative precursor for atomic layer deposition of aluminum oxide thin films

2019

Due to the safety challenges associated with the use of trimethylaluminum as a metal precursor for the deposition of alumina, different chemicals have been investigated over the years to replace it. The authors have investigated the use of aluminum tri-isopropoxide (TIPA) as an alternative alkoxide precursor for the safe and cost-effective deposition of alumina. In this work, TIPA is used as a stable Al source for atomic layer deposition (ALD) of Al2O3 when different oxidizing agents including water, oxygen plasma, water plasma, and ozone are employed. The authors have explored the deposition of Al2O3 using TIPA in ALD systems operating in vacuum and atmospheric pressure conditions. For the…

RELATIONSHIPS OF SERUM URIC ACID WITH PLASMA RENIN ACTIVITY AND PLASMA ALDOSTERONE IN PRIMARY HYPERTENSION.

2013

Introduction: In experimental studies conducted in rats, raising serum uric acid (SUA) levels resulted in stimulation of renin expression. Studies in humans exploring the association of SUA with plasma renin activity (PRA) yielded conflicting results. Moreover, little is known about the relationship between plasma aldosterone concentration (PAC) and SUA. Aim: To analyse the relationships between SUA, PRA and PAC in a group of subjects with primary hypertension. Methods: We enrolled 372 patients (mean age 45 ± 12 years; women 33 %), with untreated primary hypertension, with normal renal function and without cardiovascular complications. Results: Spearman’s rank-correlation analyses showed th…

The relationship between visible light emission and species fraction of the hydrogen ion beams extracted from 2.45 GHz microwave discharge.

2015

The relationship between Balmer-α and Fulcher-band emissions with extracted H + , H + 2 , and H + 3 ions is demonstrated for a 2.45 GHz microwave discharge. Ion mass spectra and optical measurements of Balmer-α and Fulcher-band emissions have been obtained with a Wien Filter having an optical viewport on the plasma chamber axis. The beam of approximately 1 mA is analyzed for different plasma conditions simultaneously with the measurement of light emissions both with temporal resolution. The use of visible light emissions as a valuable diagnostic tool for monitoring the species fraction of the extracted beams is proposed. peerReviewed

Photoelectron emission experiments with ECR-driven multi-dipolar negative ion plasma source

2017

Photoelectron emission measurements have been performed using a 2.45 GHz ECR-driven multi-dipolar plasma source in a low pressure hydrogen discharge. Photoelectron currents induced by light emitted from ECR zone and H− production region are measured from Al, Cu, Mo, Ta, and stainless steel (SAE 304) surfaces as a function of microwave power and neutral hydrogen pressure. The total photoelectron current from the plasma chamber wall is estimated to reach values up to 1 A for 900 W of injected microwave power. It is concluded that the volumetric photon emission rate in wavelength range relevant for photoelectron emission is a few times higher in arc discharge. peerReviewed

Cyclical generation of reconnected magnetic fields by electron pressure gra-dients

2021

The theoretical basis for the cyclical generation of macroscopic reconnected magnetic fields in low collisionality plasma regimes is formulated. The relevant process is sustained by the “thermal” energy of the electron population.In particular, an oscillatory mode propagating along and across a confining magnetic field is identified that involves the magnetic reconnection region where the ratio of the longitudinal to transverse electron thermal conductivity is relatively large. A periodic exchange of reconnected magnetic field conductivity energy with electron thermal energy is sustained within a region that remains significant even when the magnetic field configuration from which the mode …

Plasma-wall interaction studies within the EUROfusion consortium: Progress on plasma-facing components development and qualification

2017

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

VUV emission spectroscopy combined with H- density measurements in the ion source Prometheus I

2016

“Prometheus I” is a volume H− negative ion source, driven by a network of dipolar electron cyclotron resonance (ECR; 2.45 GHz) modules. The vacuum-ultraviolet (VUV) emission spectrum of low-temperature hydrogen plasmas may be related to molecular and atomic processes involved directly or indirectly in the production of negative ions. In this work, VUV spectroscopy has been performed in the above source, Prometheus I, both in the ECR zones and the bulk (far from ECR zones and surfaces) plasma. The acquired VUV spectra are correlated with the negative ion densities, as measured by means of laser photodetachment, and the possible mechanisms of negative ion production are considered. The well-e…

Urheilujuoman nauttimisen vaikutus plasmatilavuuteen, hemoglobiinikonsentraatioon ja hematokriittiin hiihtokilpailun jälkeen

2000

Kansainvälinen hiihtoliitto on ottanut käyttöön säännön, jonka mukaan kilpailuista suljetaan pois ne hiihtäjät, joiden hemoglobiinikonsentraatio (Hb) on tunti ennen kilpailua yli tietyn rajan, miehillä> 185 g • L-1 ja naisilla> 165 g • L-1 • On väitetty, että kilpailun aikainen nesteen menetys voisi lisätä hemoglobiinikonsentraatiota niin, että saataisiin vääriä positiivisia tuloksia, jos hemoglobiinikonsentraatio mitattaisiin kilpailun jälkeen. Tämän tutkimuksen tarkoituksena olikin tutkia urheilujuoman nauttimisen vaikutusta plasmatilavuuteen, hemoglobiinikonsentraatioon ja hematokriittiin 11.5 km hiihtokilpailun jälkeen. Kahdeksantoista kansallisen tason mieshiihtäjää (VOZmax 66 ± 5 ml •…