Impurity Pellet Injection Systems for Tokamak Diagnostics and Burn Control

Kuteev, B. V.; Sergeev, V. Yu.; Egorov, S.M.; Kapralov, V. G.; Khlopenkov, K.; Miroshnikov, I. V.; Polyakov, D.V.; Reznichenko, P. V.; Lang, P. T.; Büchl, K.; Cierpka, P.; Lang, R. S.; Sudo, S.

doi:10.13182/fst94-a40275

Cited by 9 publications

(4 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the same time, between 50 and 100% of the plasma thermal energy was radiated, lowering considerably the heat load in the divertor [112,242]. A similar trend is observed in the other devices [239][240][241], figure 50. The injection of a killer-pellet also allows reduction by ∼50% of the intensity of halo currents as well as the associated mechanical loads [240,242], figure 51.…”

Section: Fast Plasma Terminationsupporting

confidence: 66%

“…One of the possible methods for disruption mitigation is the injection of a 'killer'-pellet of medium-Z impurity in order to radiate in a short time interval the quasi-totality of the plasma thermal energy and to limit accordingly the heat flux onto the divertor plates. Demonstration experiments were performed in JT60-U [238,239], then in ASDEX-U, T-10 [240,241] and DIII-D [242]. In this last machine, neon or argon pellets were injected, leading-on the scale of ablation (less than 1 ms)-to a threefold increase in the density, twofold in Z eff (from 1.5 to 2.9) and to a decrease in the temperature from 2 keV to 50 eV.…”

Section: Fast Plasma Terminationmentioning

confidence: 99%

See 1 more Smart Citation

Review: Pellet injection experiments and modelling

Pégouriè

2007

Plasma Phys. Control. Fusion

125

158

View full text Add to dashboard Cite

During the last decade, significant progress has been made in the field of pellet injection with (1) the identification of the drift of the deposited material in the inhomogeneous magnetic field that opened the possibility of fuelling efficiently the plasmas from the high-field side of the torus, (2) the technique to mitigate ELMS in H-mode discharges with shallow pellet injection at high frequency and (3) with the development of high density, high performance scenarios close to the ITER requirements. Both the experimental and theoretical aspects of this domain are reviewed in this paper.

show abstract

Section: Fast Plasma Terminationsupporting

confidence: 66%

Section: Fast Plasma Terminationmentioning

confidence: 99%

Review: Pellet injection experiments and modelling

Pégouriè

2007

Plasma Phys. Control. Fusion

125

158

View full text Add to dashboard Cite

show abstract

“…Several approaches to the problem have been proposed and experimentally tested in modern devices, which have demonstrated the technical opportunities of controlling the electron avalanche development during the current quench (CQ) stage. Injection of high and low Z pellets [3,4], shuttered pellets [5,6], dispersive shell pellets [7], massive gas puffing [8], dust [9] and liquid [10] jets have been studied during the last few decades. * Author to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Disruption mitigation in tokamak reactor via reducing the seed electrons of avalanche

Sergeev¹,

Kuteev²

2021

Nucl. Fusion

View full text Add to dashboard Cite

Disruption mitigation technology remains the key factor for ensuring safe and reliable operation in future large tokamaks including ITER. A novel approach analyzed in this paper aims at mitigating the runaway avalanche (RA) development by reducing the population of runaway seeds using the tungsten projectile injection into the ITER plasma just after the thermal quench. As opposed to the scenario currently discussed by the ITER team, the approach does not involve injecting a large mass of deuterium into the tokamak vacuum vessel for collisional suppression of the RA current generated. This should significantly reduce the operational problems of the ITER technological systems dealing with fueling and pumping, isotope separation, plasma heating, etc. Collecting seeds and runaways by the projectile injected might reduce the avalanche current in ITER below the level of 1 MA and its magnetic energy by more than two orders of magnitude. A tungsten rod being 8 mm inside of the square section and 80 mm in length that crosses the plasma volume with the velocity of 0.8 km s−1 radially or tangentially seems appropriate for ITER disruption conditions. Simulations of the projectile interaction with the ITER post TQ plasma revealed that its surface temperature remains below the tungsten melting point. It is also found that a railgun using the toroidal magnetic field of the tokamak is the optimal way to accelerate such a projectile.

show abstract

“…The physics of the particle transport in plasmas is far from being established and numerous experiments have been carried out in order to derive the transport coefficients from diffusion measurements. The conventional methods of studying the impurity transport either do not provide information on the exact amount of impurity entering the plasma (as in the laser blow-off method [1]) or result in a broad initial profile of the deposited impurity (as with impurity pellet injection [2,3]). This complicates the further analysis and reduces the accuracy of transport measurements.…”

Section: Introductionmentioning

confidence: 99%

New particle transport diagnostics with tracer-encapsulated solid pellet

Khlopenkov¹,

Sudo²

2001

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

A new diagnostic method for local particle transport, which is based on injection of the tracer-encapsulated solid pellet (TESPEL), was applied for the first time in experiments on the CHS device. Such a configuration of the pellet allows the lithium hydride tracer to reach the core plasma region and be deposited within a few centimetres in the radial direction, which was confirmed by measurements with photomultipliers and CCD imaging. The radial diffusion of the fully ionized tracer is observed by means of charge exchange recombination spectroscopy with the heating neutral beam as a source. The local tracer deposition and complete ionization of the tracer greatly simplify the transport analysis and allow the use of analytic expressions for deriving the diffusion coefficient, D. With this procedure, the diffusion coefficient was determined for various plasma conditions and was found to be larger for discharges with higher electron temperature. An impurity transport code was also applied to the experimental data, which allowed more precise calculation of the transport coefficients including the pinch velocity, V . It is expected that a higher accuracy will be achieved for the case of TESPEL injection into a larger-scale plasma.

show abstract

Impurity Pellet Injection Systems for Tokamak Diagnostics and Burn Control

Cited by 9 publications

References 9 publications

Review: Pellet injection experiments and modelling

Review: Pellet injection experiments and modelling

Disruption mitigation in tokamak reactor via reducing the seed electrons of avalanche

New particle transport diagnostics with tracer-encapsulated solid pellet

Contact Info

Product

Resources

About