Generation of High-Power, Reversed-Cherenkov Wakefield Radiation in a Metamaterial Structure

Area of Science:

• Physics
• Materials Science
• Engineering

Background:

• Metamaterials offer unique electromagnetic properties not found in natural materials.
• Cherenkov radiation is produced when charged particles travel faster than the phase velocity of light in a medium.
• Wakefield acceleration is a promising technique for future high-energy particle accelerators.

Purpose of the Study:

• To demonstrate high-power reversed-Cherenkov wakefield radiation using electron bunches passing through a metamaterial structure.
• To investigate the potential of metamaterial structures for high-gradient particle accelerators.

Main Methods:

• Experimental generation of reversed-Cherenkov radiation using single and double electron bunches.
• Utilizing a metamaterial structure supporting a transverse magnetic mode with negative group velocity.
• Measuring radiofrequency (RF) power generated by the interaction.

Main Results:

• Successful demonstration of reversed-Cherenkov wakefield radiation.
• Single electron bunches generated up to 25 MW of RF power.
• Two electron bunches achieved 80 MW via coherent wakefield superposition, the highest power experienced by metamaterials without damage.

Conclusions:

• Metamaterial structures exhibit unique features suitable for high-gradient wakefield accelerators.
• The high shunt impedance and ruggedness of these structures are advantageous for power generation and acceleration.
• These findings pave the way for advanced accelerator designs, including two-beam and collinear accelerators.