Speaker
Description
Origin of negative hydrogen ($\text{H}^-$) ion beam parameter oscillation in J-PARC Radio Frequency (RF) -driven $\text{H}^-$ ion source is investigated by direct comparison between experiments and Particle-In-Cell (PIC) simulation. The bias voltage in the range from -100 to +100 V is applied between the extraction electrode (EE) and the plasma electrode (PE) under the RF plasma operation with 10 – 40 kW RF power input. The measured I-V curve of the EE with respect to the PE indicates the contribution of coextracted electrons under Cs-free condition. The PIC calculation model calculated numbers of electrons, positive ions, and $\text{H}^-$ ions reaching the EE crossing the plasma boundary formed near the PE as functions of time. The numerical simulation results of the EE current waveforms for corresponding experimental conditions are compared with the experimental results to validate the physical model employed for the simulation. Oscillation behaviors in trajectories of charged particles, equipotential surface distribution, and energy distributions visualized by the simulation model are examined for finding the factors influential upon determining the waveform of the EE current.
| Email address | takanori.shibata@kek.jp |
|---|---|
| Visitor's Visa | yes |
| Classification | Fundamental processes and modelling |