M. F. Thornton A. J. T. Holmes L. M. Lea G. O. R. Naylor
This paper presents the results of experimental studies on a number of different ' current carrying wire' type first grid electron suppressors: or ' inserts', as they shall be called throughout this paper. Extracted negative ion currents are compared for the different inserts over a range of field strengths. Currents are also compared to those extr…
PublishedL. M. Lea A. J. T. Holmes M. F. Thornton
Experiments performed in a volume production negative ion source show that the use of a tent or supercusp magnetic filter leads to a more uniform plasma at the normal extraction plane than that obtained with a dipole filter. For the tent filter geometry the extracted negative ion current density, increased as the accelerator was moved into the sour…
PublishedL. M. Lea A. J. T. Holmes M. F. Thornton G. O. R. Naylor
When a suitable accelerating voltage is applied to extract negative ions from a volume production source, electrons are also extracted. If no means of suppression is utilized, the electron current in a hydrogen plasma would typically be of the order of 80-100 times the negative-ion current. In the accelerator designs in use at Culham Laboratory, el…
PublishedAndrew J. T. Holmes
The large size of future, and possibly present day, tokamaks requires high neutral atom beam energies for current drive and heating. These injectors must also have a high electrical efficiency and this can be achieved using negative ion sources to create the beam. These large tokamaks, such as ITER or NET require a neutral beam power of around 50-1…
Published