5 papers
Nonlinear Bayesian Doppler Tomography for Simultaneous Reconstruction of Flow and Temperature
Kenji Ueda, Masaki. Nishiura
We present a nonlinear Bayesian tomographic framework for Doppler spectral imaging that enables simultaneous reconstruction of emissivity, ion temperature, and flow velocity from l…
Nonlinear Gaussian process tomography with imposed non-negativity constraints on physical quantities for plasma diagnostics
Kenji Ueda, Masaki Nishiura
We propose a novel tomographic method, nonlinear Gaussian process tomography (nonlinear GPT), that uses the Laplace approximation to impose constraints on non-negative physical qua…
Overcoming the space-charge dilemma in low-energy heavy ion beams via a multistage acceleration lens system
M. Nishiura, T. Ido, M. Okamura +3
Low-energy heavy-ion beams are fundamentally limited by severe space-charge divergence, which constrains the transportable beam current to a few microamperes in conventional electr…
Enhanced beam transport via space charge mitigation in a multistage accelerator for fusion plasma diagnostics
M. Nishiura, K. Nakamura, K. Ueda +5
Efficient transport of high-current negative ion beams is critical for accurate plasma potential diagnostics using heavy-ion beam probe (HIBP) systems in magnetically confined fusi…
High performance beam transport with multi-stage acceleration system and its application to plasma potential measurement in fusion plasmas
Kaori Nakamura, Masaki Nishiura, Kenji Ueda +4
In accelerators, ion beams are often accelerated using electrostatic accelerating tubes. This paper reports on a method to improve the beam transport efficiency without adding new…