Plasma Accelerator Driver Using Sideband Pulse Trains
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Solution Overview
Problem
Conventional RF accelerators are large and expensive due to electric field limitations, while current laser-driven plasma accelerators have low repetition rates and low wall-plug efficiencies, making them unsuitable for high mean current applications.
Innovation Solution
A driver for plasma accelerators using a first laser pulse with a duration less than the electron plasma period to generate a wake, followed by a second temporally smooth laser pulse interacting with the wake to form red and blue shifted sidebands, which are then phase-shifted to create a train of coincident pulses for particle acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional RF fields are used for particle acceleration, then high repetition rates and high mean currents can be achieved, but the accelerator size becomes very large and expensive due to electric field limitations
Solution Approach 1:
The invention changes the fundamental parameter of electric field generation from RF fields to plasma wakefields driven by laser pulses. This allows achieving much higher electric fields (GV/m scale) in compact volumes, resolving the contradiction between acceleration efficiency and device size.
Solution Approach 2:
The invention replaces the conventional RF electromagnetic field system with a plasma-based acceleration system driven by optical laser fields. This substitution enables compact high-gradient acceleration while maintaining high repetition rates through modern laser technology.
2Volume of moving object
If titanium:sapphire lasers are used as drivers for plasma accelerators, then compact acceleration is achieved, but the repetition rate becomes very low (less than 10 Hz) and wall-plug efficiency becomes extremely low (less than 1%)
Solution Approach 1:
The invention changes the laser system parameters from traditional titanium:sapphire lasers to modern high-repetition-rate laser systems with improved wall-plug efficiency. This allows plasma accelerators to operate at high repetition rates (kHz scale) while maintaining compact size.
Solution Approach 2:
The invention employs periodic laser pulse trains at high repetition rates to drive plasma wakes continuously, enabling high mean current output. The periodic action of synchronized laser pulses creates stable plasma waves for efficient particle acceleration.
3Volume of moving object
If a single short laser pulse is used to generate plasma wake, then compact acceleration is achieved, but the average power and repetition rate remain limited
Solution Approach 1:
The invention uses periodic sequences of short laser pulses at high repetition rates to drive plasma wakes. This periodic action accumulates energy over time, achieving high average power output while maintaining the compact benefits of single-pulse plasma acceleration.
Solution Approach 2:
The invention ensures continuous plasma wake generation through high-repetition-rate laser pulsing. The continuous action of repeatedly driving plasma waves maintains stable acceleration conditions, enabling high average power and high mean current output from a compact device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables high average-power, high repetition rate, and high efficiency laser operation, suitable for generating intense pulses for applications like free-electron lasers and particle physics, overcoming the limitations of conventional RF and current plasma accelerators.
Implementation Method 1
the first laser pulse is arranged to generate a plasma wake in the volume of plasma
Implementation Method 2
the second laser pulse is arranged to interact with the plasma wake to form a plurality of red-shifted regions and a plurality of blue-shifted regions along the length of the second laser pulse, thus forming a plurality of red-shifted sidebands and a plurality of blue-shifted sidebands in the spectrum of the second laser pulse
Implementation Method 3
the dispersive optical device is arranged to introduce a chromatic dispersion in the second laser pulse, so as to shift the spectral phases of the plurality of red-shifted sidebands and the plurality of blue-shifted sidebands, so as to temporally shift the plurality of red-shifted regions and the plurality of blue-shifted regions relative to each other
Data Source
AI summary
A driver (1) for a plasma particle accelerator includes a plasma (10) and laser system(s) (2) that generate first and second pulses. The first pulse (4) has a duration less than the electron plasma period. The second pulse (6) is temporally smooth and has a duration greater than the electron plasma period and less than the ion plasma period. The first pulse generates a plasma wake and the second pulse interacts with the wake to form red and blue-shifted sidebands. The driver also includes a dispersive optical device (20) that introduces a chromatic dispersion to shift the spectral phases of the red and blue-shifted sidebands, to temporally shift them relative to each other, so as to form coincident pulses (22) for generating a plasma wake in a plasma particle accelerator (26).