High-gradient plasma-wakefield acceleration with two subpicosecond electron bunches.

Area of Science:

• Plasma physics
• Particle acceleration
• Accelerator science

Background:

• Plasma wakefield acceleration (PWFA) offers a promising avenue for compact and high-gradient particle accelerators.
• Previous research has explored PWFA, but controlled acceleration of trailing bunches with precise phase control remains a challenge.
• Sub-picosecond electron bunches are crucial for efficiently coupling to plasma waves.

Purpose of the Study:

• To experimentally demonstrate controlled acceleration of a trailing electron bunch in a plasma wakefield.
• To investigate the feasibility of achieving high accelerating gradients for short-pulse electron bunches.
• To explore the effect of plasma density on the phase and acceleration of the trailing bunch.

Main Methods:

• A plasma wakefield experiment utilizing two 60 MeV sub-picosecond electron bunches.
• Plasma generation via capillary discharge.
• Adjustment of the trailing bunch's phase relative to the plasma wave by tuning plasma density.

Main Results:

• The trailing electron bunch experienced a loaded accelerating gradient of 150 MeV/m.
• The experiment successfully demonstrated controlled acceleration of the short-pulse trailing bunch.
• The phase of the trailing bunch was effectively controlled by adjusting plasma density.

Conclusions:

• This study presents the first direct experimental demonstration of high-gradient, controlled acceleration of a short-pulse trailing electron bunch in a high-density plasma.
• The results validate the potential of PWFA for future high-energy particle accelerators.
• Precise control over plasma density enables tailored acceleration gradients for trailing bunches.