Detection of lost alpha particle by concealed lost ion probe

Area of Science:

• Nuclear Fusion Engineering
• Plasma Physics
• Particle Confinement

Background:

• Alpha particles are crucial for self-heating in fusion plasmas.
• Understanding alpha particle loss is vital for reactor design and performance.
• Previous methods for detecting lost particles had limitations.

Purpose of the Study:

• To investigate the detectability of lost alpha particle orbits using a concealed lost ion probe (CLIP).
• To determine the factors influencing the detection of different orbit types (passing vs. trapped).
• To explore the optimization of CLIP placement for enhanced detection capabilities.

Main Methods:

• Full orbit-following calculations were performed for lost alpha particle trajectories.
• Simulations analyzed the interaction of particles with the CLIP and first wall.
• The influence of reflection points and pitch angles on detection was examined.

Main Results:

• The CLIP can detect certain escaping alpha particle orbits, particularly trapped ones.
• Trapped orbits are more readily detected than passing orbits due to their reflection points and pitch angles (<90° at CLIP).
• The detection window of the CLIP is dependent on the particle's final orbit and reflection location.

Conclusions:

• Concealed lost ion probes offer a viable method for detecting lost alpha particles.
• CLIPs are more effective for trapped particle orbits, which are reflected before impacting the first wall.
• Strategic placement of CLIPs is essential for maximizing the detection of lost alpha particles and improving fusion reactor diagnostics.