Experimental Demonstration of Acceleration and Focusing of Magnetically Confined Plasma Rings

Hammer, J.H.; Hartman, C.W.; Eddleman, J.L.; McLean, H. S.

doi:10.1103/physrevlett.61.2843

Cited by 65 publications

(33 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Compact toroid spheromaks are nearly force-free axisymmetric plasma rings in which the toroidal and poloidal magnetic fields are of comparable magnitude and have the desirable properties of stability, robustness and long lifetimes, allowing acceleration to very high velocities [3].…”

Section: Introductionmentioning

confidence: 99%

Effects of CT injector acceleration electrode configuration on tokamak penetration

Yee

Bellan

1998

Nucl. Fusion

View full text Add to dashboard Cite

ABSTRACT. Through compact toroid (CT) injection experiments on the TEXT-U tokamak (with BT 10 kG and IP 100 kA), it has been shown that the acceleration electrode configuration, particularly in the vicinity of the toroidal field (TF) coils of the tokamak, has a strong effect on penetration performance. In initial experiments, premature stopping of CTs within the injector was seen at anomalously low TF strengths. Two modifications were found to greatly improve performance: (a) removal of a section of the inner electrode and (b) increased diameter of the 'drift tube' (which guides the CT into the tokamak after acceleration). It is proposed that the primary drag mechanism slowing CTs is toroidal flux trapping, which occurs when a CT displaces transverse TF trapped within the flux conserving walls of the acceleration electrodes (or drift tube). For a simple two dimensional (2-D) geometry, a magnetostatic analysis produces a CT kinetic energy requirement of 1 2 ρv 2 ≥ α B 2 0 /2µ0 , with α = 2/(1 − a 2 /R 2 ) a dimensionless number that is dependent on the CT radius a normalized by the drift tube radius R. For a typical CT, this can greatly increase the required energies. A numerical analysis in 3-D confirms the analytical result for long CTs (with length L such that L/a > ∼ 10). In addition to flux trapping, the CT shape is also shown to affect the energy criterion. These findings indicate that a realistic assessment of the kinetic energy required for a CT to penetrate a particular tokamak TF must take into account the interaction of the magnetic field with the electrode walls of the injector.

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of CT injector acceleration electrode configuration on tokamak penetration

Yee

Bellan

1998

Nucl. Fusion

View full text Add to dashboard Cite

show abstract

“…The magnetic pressure gradients produced as a consequence of such waves have been shown to have an essential role in the generation of astrophysical jets [1][2][3][4]. These waves also underpin the formation and acceleration of spheromak and compact toroid plasmas [5][6][7][8][9][10], as well as the recent advances in plasma-jet driven magnetized target fusion and shear-flow-stabilized Z pinch schemes [11][12][13]. Due to increasing interest in these plasma phenomena, there is a critical need for a reliable model that accurately predicts the behavior of plasmas formed and sustained by MHD ionization waves.…”

mentioning

confidence: 99%

Evidence of Branching Phenomena in Current-Driven Ionization Waves

2015

View full text Add to dashboard Cite

“…This phenomenon is not revealed by the magnetic probes because they are measuring B z , and the trailing plasma may not contain any B z component. Trailing plasma is a common phenomenon in CTs and other accelerated plasmas [32,49].…”

Section: Density Measurementsmentioning

confidence: 99%

Repetitive operation of the University of Saskatchewan Compact Torus Injector

Pant

Hirose

Xiao

2010

Radiation Effects and Defects in Solids

View full text Add to dashboard Cite

Development of fueling technologies for modern and future tokamak reactors is essential for their implementation in a commercial energy production setting. Compared to the presently available fueling technologies, gas or cryogenic pellet injection, compact torus injection presents an effective and efficient method for directly fueling the central core of tokamak plasmas. Fueling of the central core of a tokamak plasma is pivotal for providing efficient energy production. The central core plasma of a reactor contains the greatest density of fusion processes. For consistent and continuous fueling of tokamak fusion reactors, compact torus injectors must be operated in a repetitive mode.The goal of this thesis was to study the feasibility of firing the University of Saskatchewan Compact Torus Injector (USCTI) in a repetitive mode. In order to enable USCTI to fire repetitively, modifications were made to its electrical system, control system and data acquisition system. These consisted primarily of the addition of new power supplies, to enable fast charging of the many capacitor banks used to form and accelerate the plasma. The maximum firing rate achieved on USCTI was 0.33 Hz, an increase from the previous maximum firing rate of 0.2 Hz achieved at UC Davis.Firing USCTI in repetitive modes has been successful. It has been shown that the CTs produced in any given repetitive series are properly formed and repeatable. This is made evident through analysis of data collected from the CTs' magnetic fields and densities as they traveled along the injector barrel. The shots from each experiment were compared to the series' mean data and were shown to be consistent over time.Calculations of their correlations show that there are only minimal deviations from shot to shot in any given series.ii

show abstract

Experimental Demonstration of Acceleration and Focusing of Magnetically Confined Plasma Rings

Cited by 65 publications

References 7 publications

Effects of CT injector acceleration electrode configuration on tokamak penetration

Effects of CT injector acceleration electrode configuration on tokamak penetration

Evidence of Branching Phenomena in Current-Driven Ionization Waves

Repetitive operation of the University of Saskatchewan Compact Torus Injector

Contact Info

Product

Resources

About