The motional stark effect mse diagnostic deployed on the alcator cmod tokamak previously experienced unacceptable calibration drift and sensitivity to partiallypolarized background light that limited its ability to measure magnetic. Atomic data for calculation of the intensities of stark. The report focuses mainly on two areas of the motional stark e ect mse with respect. Pdf realtime motional stark effect in jet diogo alves. Amici prism optomechanical design process lens mounting iter. Fast motional stark effect diagnostic measurements of. In this paper, the existing forward model which describes the mse data is extended by the zeeman effect, finestructure, and relativistic corrections in the interpretation of the mse spectra for different experimental conditions at the. Motional stark effect diagnostic pilot experiment for mast. Design of the new imaging motional stark effect diagnostic at. We have implemented a spectral motional stark effect diagnostic for spatially localized measurements of magnetic.
Read realtime motional stark effect in jet, fusion engineering and design on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Motional stark effect measurements of the local magnetic field in high temperature fusion plasmas authors 3 this paper is organized as follows. A photoelasticmodulatorbased motional stark effect polarimeter for iter that is insensitive to polarized broadband background reflections a. This diagnostic allows us to measure locally the strength and direction of the magnetic field. Internal transport barrier itb and q profile control, has motivated the development of a realtime motional stark effect mse system.
Measurements of the magnetic pitch angle are used with magnetic equilibrium reconstruction codes such. A multichannel motional stark effect mse diagnostic is under development for providing accurate information of the internal magnetic field on east tokamak. The motional stark effect diagnostic can provide a direct measurement of the magnetic field orientation but the derivation of the qprofiles requires a simulation of the magnetic equilibrium taking into account inputs from several other diagnostics. However, the addition of an estimated diamagnetic term. Spectral motional stark effect diagnostic on the gasdynamic trap the stark effect is a result of the breaking of energylevel degeneracy of an atom in an external electric. Laoanalysis of current drive using mse polarimetry c. On the influence of zeeman effect on magnetic equilibrium. Motional stark effect diagnostics for kstar request pdf. Conventional albeit very narrow interference filters isolate. Combined zeeman and motional stark effect measurements.
Pdf motional stark effect diagnostic pilot experiment. Combined zeeman and motional stark effect measurements of local magnetic effects on asdex upgrade preprint of. A7a,40 kev diagnostic neutral hydrogen beam was focused to a current density of 0. A new analysis scheme has been developed to infer both the pitch angle and the magnitude of the. As the beam neutrals move with high velocity, v, through the. A spectrally resolved motional stark effect mse diagnostic has been implemented for the tj. Development of the motional stark effect with laser.
The purpose of this work is to assess spectral motional stark effect diagnostics for study ing plasma. Development of the bstark motional stark effect diagnostic. Thorman et althe prototype imaging motional stark effect diagnostic for asdex upgrade o. This results in partial blending of observed spectral lines and consequent masking of doppler or stark effect. The stark effect is the shifting and splitting of spectral lines of atoms and molecules due to the presence of an external electric field. Ii stellarator to quantify the magnitude and pitch of components of the magnetic field created in this magnetic confinement device. The utilization of the motional stark effect mse experienced by the neutral hy drogen or deuterium injected into magnetically. Eliminating spikes observed in motional stark effect with colissionally induced fluorescence diagnostics zachary e. The light collected by the internal optics passes through a vacuum window and is relayed to a fiber optic. A spectral line shape analysis of motional stark effect. Simulation of the motional stark effect on cmod using. Design of the new imaging motional stark effect diagnostic.
The motional stark effect enables internal magnetic. The motional stark effect mse diagnostic is used to measure the radial magnetic pitchangle profile in neutralbeamheated plasmas. Recent citations a faraday effect polarimeter for fast magnetic dynamics measurement on diiid j. A new diagnostic, bstark, has been developed at the diii d tokamak for measurements of the magnitude and direction of the internal magnetic field. Simulation of the multichannel motional stark effect. Combined zeeman and motional stark effect measurements of. First results from the imaging motional stark effect diagnostic on asdex upgrade o. Rice this is a preprint of a paper to be presented at the seventh international conference on plasma physics and controlled nuclear fusion, november 28 through. Pdf influence of nonlocal thermodynamic equilibrium and.
A high spatial resolution stokes polarimeter for motional. In the frame of reference of an atom moving transverse to a magnetic. Method for correction of measured polarization angles from. Rfp equilibrium is substantially determined by selfgenerated plasma currents internal b measurements critical to physics understanding in presentday rfp devices, internal b is relatively small 1 t or less. Motional stark effect measurements of the local magnetic. Exsp203 determination of q profiles in jet by consistency. A highprecision spectral motional stark effect mse diagnostic provides internal magnetic field measurements for madison symmetric torus mst plasmas. The motional stark effect diagnostic mse has been widely applied to measure magnetic field pitch angle in high field toroidal plasma devices since its. Development of the motional stark effect with laserinduced. Motional stark effect diagnostics for kstar springerlink. Motional stark effect mse spectroscopy represents a unique diagnostic tool. Future development of the motional stark effect utilizing laser induced fluorescence to access much lower magnetic fields will be discussed. The motional stark effect diagnostic mse was invented by dr. This diagnostic uses the spacing of the stark lines to measure the magnitude of the magnetic field, and the intensities of the pi.
Beam emission spectroscopy motional stark effect diagnostic on textor kat, j. The motional stark effect polarimeter in the hl2a tokamak rev. Particle deposition and optical response of iter motional stark effect diagnostic first mirrors, j. Effect of plasma radial electric field on motional stark effect measurements and equilibrium reconstruction b. First results from the imaging motional stark effect. Optical and mechanical design of cmod motional stark effect. To assist the ongoing design and implementation of the diagnostic, an optimization study is performed using alcbeam and nbass codes. Eliminating spikes observed in motional stark effect with. Due to the neutral particle velocityv with respect to the magnetic. The motional stark effect diagnostic mse has been widely applied to measure magnetic.
Brubaker carsonnewman college, jefferson city, tn 37760, elizabeth l. Levinton in 1989 and has subsequently become the worldwide touchstone for the measurement of internal magnetic fields in high temperature plasma experiments. The mse diagnostic allows the measurement of local magnetic fields in different locations along the neutral beam path providing, therefore, local. Pdf spectra polarimetry of the motional stark effect at.
The motional stark effect diagnostic mse is presently a widely accepted technique for measuring the magnetic. Currently, mst uses two spatial viewson the magnetic axis and on the midminor offaxis radius, the latter added recently. Motional stark effect imaging first results on the diiid tokamak alex thorman et ala photoelasticmodulatorbased motional stark effect polarimeter for iter that is insensitive to polarized broadband background reflections a. An overview of the motional stark effect diagnostic on diii.
The diagnostic relies upon the measurement of the polarization direction of stark split dalpha emission from injected fast neutral atoms in a magnetic field. The cmod mse measures the local electric field direction by measuring the polarization angle of balmeralpha n2 emission from a radially injected hydrogen diagnostic neutral beam 50 kev, 5 a, 50 ms. Oct 28, 2010 a motional stark effect mse diagnostic is now installed and operating routinely on the mast spherical tokamak, with 35 radial channels, spatial resolution of. Fast method for radial electric field correction of motional. A worldwide experimental program to study these issues is underway e. Fast method for radial electric field correction of.
A motional stark effect mse instrument is being installed on the alcator cmod tokamak at mit. Allain, 107 2 implantation leading to bubble formation, surface blistering, and formation of porous deposited layers. A motional stark effect mse diagnostic is now installed and operating routinely on the mast spherical tokamak, with 35 radial channels, spatial resolution of. Simulation of the motional stark effect on cmod using msesim. Eindhoven university of technology master beam emission. Motional stark e ect an atom moving with a constant velocity v in a magnetic eld b experiences in its moving frame of reference a lorentz electric eld e l v b. We have developed a diagnostic to measure the motional stark effect mse on textor94. Request pdf motional stark effect diagnostics for kstar the motional stark effect mse diagnostic is used to measure the radial magnetic pitchangle profile in neutralbeamheated plasmas. A nonstatistical atomic model for beam emission and motional stark effect diagnostics in fusion plasmasa rev. Motional stark effect diagnostic fundamentals nova photonics. First the motional stark effect and its basic features as plasma diagnostic are briefly introduced. A photoelasticmodulatorbased motional stark effect. Foley nova photonics, princeton, nj 08540 abstract avalanche photodiodes apd used at the national spherical torus experiment nstx make. Engineering upgrades to the motional stark effect diagnostic.
In this paper, the existing forward model which describes the mse data is extended by the zeeman effect, finestructure, and relativistic corrections in the interpretation of the mse spectra for different experimental conditions at the tokamak asdex upgrade. Adas application to lowfield motional stark effect. The mse has its primary collection optics inside the vacuum vessel. The motional stark effect diagnostic 1 is now considered as an essential diagnostic for an accurate determination of current profiles in tokamak discharges. Fast motional stark effect diagnostic measurements of hybrid. Motional stark effect diagnostic pilot experiment for mast rev.
A spectral line shape analysis of motional stark e ect spectra. A spectral line shape analysis of motional stark effect spectra. A ten channel motional stark effect diagnostic has been installed on alcator cmod to measure the plasma internal magnetic pitch angle profile. For this reason, this diagnostic is implemented on most of the existing machines. Instrumentation for a multichord motional stark effect. Fast method for radial electric field correction of motional stark effect data in diiid database results conclusions overall, it seems as though the partial e r method creates some real improvement over shots with no e r analysis and ought to be used routinely in efit reconstructions. Available information in 2d motional stark effect imaginga. Combined with the mse it forms the socalled combined zeeman stark e ect pattern 10,11,12. This mse diagnostic will provide measurements of the spatial profile of the internal poloidal magnetic field. The definition of the torus coordinates are shown in c. Optical and mechanical design of cmod motional stark.
Design of the new imaging motional stark effect diagnostic at asdex upgrade a. The diagnostic relies upon the measurement of the polarization direction of starksplit dalpha emission from injected fast neutral atoms in a magnetic field. Rice this is a preprint of a paper to be presented at the seventh international conference on plasma physics and controlled nuclear fusion, november 28 through december 1,1995, tokai, japan and to be published in the proceedings. Pdf a motional stark effect mse diagnostic is now installed and operating routinely on the mast spherical tokamak, with 35 radial channels, spatial. The motional stark effect diagnostic mse is the main tool for the. The motional stark effect mse diagnostic the motional stark effect diagnostic mse was invented by dr. The motional stark effect diagnostic on alcator cmod core. On the motional stark effect diagnostic for iter crpp. The same definition is given for the normalized toroidal flux radius. These individual components are polarized, so that selective measurement of the polarization angle. Detection and application of doppler and motional stark. The perturbation caused by zeeman e ect and motional stark e ect are represented by the terms hb and hel, respectively and is calculated in the next sections. Adas application to lowfield motional stark effect diagnostics stark effect diagnostics jinseok ko. Jun 01, 2004 the increasing importance of realtime measurements and control systems in jet experiments, regarding e.
Pdf the motional stark effect diagnostic on textor94. The direction of polarization of the emitted radiation provides a measure of the local magnetic field direction or pitch angle. Measurements of the magnetic pitch angle are used with magnetic equilibrium. This results in a spectral splitting and polarization of the emitted radiation, known as the stark effect. The report focuses mainly on two areas of the motional stark e ect mse with respect to neutral beam atoms entering in a tokamak. The bstark system is a version of a motional stark effect mse diagnostic based on the stark split dalpha emission from injected neutral beams.
The measurement of poloidal fields using the motional. Its utility is applicable to any high field fusion energy experiment containing a neutral beam. In the frame of reference of the atom, there is an electric field, even if there is none in the laboratory frame. The utilization of the motional stark effect mse experienced by the neutral hydrogen or deuterium injected into magnetically confined high temperature plasmas is a well established technique to. Detail is also given to the labelling of quantum states when dealing with the mse.
The mse diagnostic analyses light emitted by neutral beam particles usually hydrogen h or deuterium d. Internship report simulation of the motional stark e. In this paper the combined zeeman motional stark e ect is exploited by a forward model to measure variations in the fast ion pressure pro les in a high discharge scenario. The light collected by the internal optics passes through a vacuum window and is relayed to a fiber optic array. G aa22269 qprofile measurements with motional stark effect in dind by b. Stark effect measurements with beam atoms and zeeman effect. Particle deposition and optical response of iter motional. Twopoint motional stark effect diagnostic for madison. A highprecision spectral motional stark effect mse diagnostic provides internal magnetic. Review of scientific instruments 84, 063507 20 a high spatial resolution stokes polarimeter for motional stark effect imaging alex thorman, clive michael, and john howarda plasma research laboratory, research school of physics and. A spectrally resolved motional stark effect diagnostic for. Wolf 1, asdex upgrade team 1 1 max planck institut fur plasmaphysik, garching and greifswald, germany introduction motional stark effect mse diagnostics are some of the few diagnostics capable of providing.
If an atom is moving in a magnetic field, the lorentz force will act in opposite directions on the nucleus and the electrons, just as an electric field does. It is the electricfield analogue of the zeeman effect, where a spectral line is split into several components due to the presence of the magnetic field. Available information in 2d motional stark effect imaginga mathew creese and john howard plasma research laboratory, australian national university, canberra act 0200, australia. Student theses are made available in the tue repository upon obtaining the required degree. Allain, 107 2 implantation leading to bubble formation, surface blistering, and formation of porous deposited. Recent citations motional stark effect imaging first results on the diiid tokamak alex thorman et ala photoelasticmodulatorbased motional stark effect polarimeter for iter that is. Current density profile in tokamaks equilibrium reconstructions motional stark effect and zeeman heating beamsli beam optical system. Avalanche photodiode detectors with digital phasesensitive. The results are consistent with results obtained from equilibrium solver. A photoelasticmodulatorbased motional stark effect polarimeter for. Realtime motional stark effect in jet, fusion engineering.
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