Covariant analysis of accelerating charged beams and plasmas

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The aim of the proposed work is to contribute to the development of future high-energy and future low-energy particle accelerators. Considerable success has been enjoyed by high-energy particle physics in helping to explain the fundamental structure of the world around us. However, on-going progress in this field relies on novel particle accelerator development, which itself poses considerable physics and engineering challenges. As particle accelerators become more powerful they also become prohibitively large and expensive. Innovative acceleration schemes are required if ever higher energy experiments are to remain practical. This is clearly illustrated by the 30km long ILC (International Linear Collider), designed on conventional acceleration schemes, and the more radical CLIC (Compact Linear Collider) which promises to achieve particle energies that are three times greater over the same accelerator length. CLIC works by employing two particle beams operating like a transformer. A drive beam composed of long bunches of electrons is accelerated and converted into bunches of much shorter length which are then decelerated to power the main beam accelerator. A sound knowledge of the detailed bunch dynamics during the conversion stage is critical for the success of this novel machine. Lower energy accelerators are one of the components of intense light sources used to study the structure of matter. In conventional free-electron lasers, bunched electrons are accelerated using the electric fields inside radio-frequency microwave cavities and then forced to emit coherent light by injection into an undulator. The cost and size of such light sources, mostly due to the accelerator component, prohibit housing them in university departments and they are only accessible as expensive large shared facilities. However, laser-driven plasma wakefield acceleration is a highly promising alternative acceleration scheme that has seen much experimental success in recent years. This radical approach exploits the huge electric fields created by a laser pulse in a plasma to accelerate electrons in the wake behind the laser pulse. It promises to deliver highly compact ( table-top ) sources of intense electromagnetic pulses of femtosecond duration for probing matter on unprecedented temporal and spatial scales. In the future, university departments could be housing their own light sources based on this concept. However, a number of important issues remain to be resolved because the accelerated electron bunches do not yet satisfy all the stringent criteria needed to produce electromagnetic pulses of the necessary quality. The proposed work centres on the development of new and powerful mathematical models to address fundamental issues in CLIC and laser-driven plasma wakefield acceleration. Both acceleration schemes involve detailed dynamics of collections of interacting charged particles and the proposed work seeks to support their on-going development.