UKAEA Papers

"The Physics of the Preferred Plasma Scenario for STEP"

• Hendrik Meyer
• the STEP Plasma Control Heating & Current Drive Team

With steady progress on ITER project and the design of DEMO, the international community is now entering an era in which fusion power on the grid could become a reality within the next 20 – 30 years. In this environment the UK has started the ambitious Spherical Tokamak for Energy Production (STEP) programme, aiming to develop a compact protot…

"Electron Bernstein Wave (EBW) current drive profiles and efficiency for STEP"

• T. Wilson
• S.J. Freethy
• M. Henderson
• A Köhn-Seeman
• I. Konoplev
• S. Saarelma
• D. Speirs
• R.G.L. Vann
• the STEP team

The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program is now exclusively investigating concepts using microwave-based heating and current drive (HCD) systems. Electron Bernstein Wave (EBW) HCD is a relatively immature technology compared to Electron Cyclotron (EC) HCD but is of interest due to the promise of high current…

"Initial results from the SPIDER beamlet current diagnostic"

• A. Shepherd
• B. Pouradier Duteil
• T. Patton
• A. Rigoni
• G. Serianni
• E. Sartori. A. Pimazzoni

SPIDER (Source for the Production of Ions of Deuterium Extracted from a Radio frequency plasma) is the full scale prototype for the ITER Heating Neutral Beam (HNB) source. Driven by four driver coil pairs powered by oscillators the SPIDER source plasma exhibits fluctuations in a range of frequencies that have been observed by Langmuir probes and So…

"Tritium operation of the JET neutral beam systems and Tritium NBI power calculations"

• D B King
• M Nicassio
• A Ash
• C. Balshaw
• A. Barth
• D. Ciric
• I E Day
• E Delabie
• H. El-Haroun
• T. T. C. Jones
• D Keeling
• R King
• S. Marsden
• R McAdams
• A. McShee
• S. Merriman
• A Shepherd
• R. Sharma
• I Turner
• T. Wilson

Neutral Beam Injection (NBI) is a very flexible auxiliary heating method for tokamak plasmas, capable of being efficiently coupled to the various plasma configurations required in the Tritium and Deuterium–Tritium Experimental campaign (DTE2) to be undertaken in the JET device. In particular, experiments for high fusion yield and alpha particl…

"Modelling of MAST Upgrade Neutral Beam Re-ionisation and the Impact on the Beamline Ducts and In-vessel Components"

• A. Shepherd
• R. Akers
• A. Barth
• I.E. Day
• G. Fishpool
• R. McAdams
• R. Tivey
• R. Verhoeven

Neutral beam injection is one of the primary auxiliary heating systems for tokamak plasmas. Once the neutral beam leaves the neutraliser collisions with background neutral particles in the beamline and tokamak vessel re-ionises part of the neutral beam. These particles can be deflected by the tokamak magnetic field, potentially damaging unshielded …

"Energy spreading and stabilisation of plasma by application of a high frequency electric field"

• LG Kuo-Petravic
• M Petravic
• DR Sweetman
• EG Murphy
• RM Sinclair
• E Thompson

"The ionization of excited hydrogen atoms by strong electric fields"

• AC Riviere
• DR Sweetman

"Further remarks on the finite larmor radius stabilization theory for mirror machines"

• LG Kuo
• EG Murphy
• M Petravic
• DR Sweetman

"Ion source backplate loading due to backstreaming electrons in the JET EP2 neutral beam injectors"

• I. Turner
• R. McAdams
• W. Arter
• A. Ash
• M. Barnard
• D. Ciric
• I. Day
• D. Keeling
• D. King
• C. Lane
• M. Nicassio
• T. Robinson
• A. Shepherd
• J. Zacks

Increased neutralisation and hence injected neutral beam power can be achieved by increasing the neutraliser target. This has the potential to increase the loading on the ion source backplate due to backstreaming electrons. Measurements of the backplate power loading due to backstreaming electrons are presented for the JET EP2 neutral beam injector…

"Kinetic study of plasma current start-up under EBW power in tokamak plasmas"

• E.J. du Toit
• M.R. O'Brien
• R.G.L. Vann

Tokamak plasma current start-up assisted by Electron Bernstein waves (EBW) has been demonstrated successfully in a number of experiments. The dynamic start-up phase involves a change in field topology, as the initially open magnetic field lines form closed flux surfaces (CFS) under the initiation of a plasma current. This change in field topology w…