Our interdisciplinary collaboration uses our backgrounds in mathematics, physics and computer science to develop new codes and techniques to more accurately simulate and optimize particle accelerators. Here are some of the projects we are currently involved in:
When the electron bunches are forced to traverse a curved trajectory, they emit bright ultraviolet or x-ray radiation. The electron machines which produce such radiation, called synchrotron light sources, are powerful tools for cutting edge research in physics, biology, chemistry, energy, medicine and other fields. As the brightness and energy of these synchrotron light sources is extended beyond present levels, it becomes necessary to develop new computational modeling capabilities. One of the most critical needs is to develop efficient computer codes for simulating collective effects that severely degrade beam quality, such as coherent synchrotron radiation (CSR) and CSR-driven micro-bunching instability (Terzić & Bassi 2011).
We are developing an innovative code for high-performance simulations of synchrotron light sources which uses massively parallel computation on graphical processing units (GPUs) (Arumugam et al. 2013a, Arumugam et al. 2013b, Arumugam et al. 2015) and wavelet methodology (Terzić, Pogorelov & Bohn 2007, Bohn et al. 2006).
Long-term simulation of the beam dynamics for millions or billions of turns in a storage ring or a collider are a direct way to validate the dynamical stability of the ring's design. This is highly desirable for the design and optimization of existing and figure storage rings and colliders, such as LHC, RHIC, LHeC and electron-ion colliders. However, such long-term simulations have been prohibitive due to their heavy computational load. Various techniques of estimating the long-term dynamical stability based on relatively short-term simulations may not provide the necessary level of confidence. One particular complication of simulating collider beam dynamics is the necessity to account for the beam-beam interaction, which is an integral part of the collider dynamics and must be solved for each bunch crossing, with the solution coming at the high computational cost. We are developing algorithms specifically crafted to exploit fully the massive parallelism offered by the modern GPUs, thereby rendering the long-term beam-beam simulations tractable.
Accelerator physics deals with intricate systems which depend on many interrelated specifications/variables and physical quantities. One of its main goals is to design and operate accelerators so as to achieve an efficient interplay between these many quantities, thereby optimizing their performance. This is why genetic algorithms (GAs)—efficient, robust, multidimensional nonlinear optimization tools—are crucially important.
We implemented a parallel GA paradigm and applied it to a number of problems in accelerator physics, demonstrating that many previously intractable problems are now well within reach of GA optimization (Hofler et al. 2013, Terzić et al. 2014).
Thomson sources of electromagnetic radiation utilizing relativistic electrons have seen increased use in fundamental physics research in the recent years. The small frequency bandwidth of the scattered radiation is highly desirable for applications in nuclear physics, medicine and homeland security. As the intensity of the incident laser pulse increases, the bandwidth of the emitted radiation increases. We have recently shown that a judicious frequency modulation of the laser pulse can completely counteract this increase in bandwidth in Thomson sources (Terzić et al. 2014).
Our current efforts focus on:
- Studying the effects of the electron beam energy spread on the spectrum of the backscattered radiation.
- Generalizing the frequency modulation to Compton regime when electron recoil may not be neglected.