Electromagnetic waves exist as radiation of energies from charges and other quantum processes. They include radio waves, microwaves, light and X-rays. Mobile phones communicate by transmitting radio waves.
It takes a tremendous amount of computer simulations to create a device like an MRI scanner that images the brain by detecting electromagnetic waves propagating through tissue. Those simulations can take days or months to identify how the electromagnetic waves will react when they encounter the materials in the device. Because of the cost, there is a limit to the number of simulations typically done for these devices.
With funding from the Army Research Office, in a study, published in the SIAM Journal on Scientific Computing , Southern Methodist University (SMU) researchers revealed a faster algorithm for these simulations. It is a more efficient and less expensive way to predict the behaviour of waves.
"We can reduce the simulation time from one month, to maybe one hour", stated lead researcher Wei Cai, SMU Clements Chair of applied mathematics. "We have made a breakthrough in these algorithms."
"Electromagnetic waves are central to many important applications in sensing, power, and communication. Being able to conduct related simulations faster and less expensively will have many military applications", stated Dr. Joseph Myers, Army Research Office Mathematical Sciences Division chief. ARL is an element of the U.S. Army Combat Capabilities Development Command's Army Research Laboratory. "For example, this work will help create a virtual laboratory for scientists to simulate and explore quantum dot solar cells, which could produce extremely small, efficient and lightweight solar military equipment."
The new algorithm modifies a mathematical method called the fast multipole method, or FMM, which was considered one of the top 10 algorithms in the 20th century.
Using this new algorithm, the computer simulations map out how materials in a device like semiconductor materials will interact with light, in turn giving a sense of what a particular wave will do when it comes in contact with that device.
An engineer or mathematician would be able to use this new algorithm to test a device whose job is to pick out a certain electromagnetic wave. For instance, it could be used to test designs for a solar light battery that lasts longer and is smaller than currently exists.
"To design a battery that is small in size, you need to optimize the material so that you can get the maximum conversion rate from the light energy to electricity", Wei Cai stated. "An engineer could find that maximum conversion rate by going through simulations faster with this algorithm."
The algorithm could also help an engineer design a seismic monitor to predict earthquakes by tracking elastic waves in the earth, Wei Cai noted.
"These are all waves, and our method applies for different kinds of waves", he stated. "There are a wide range of applications with what we have developed."
The computational system used for this project, the SMU MANEFRAME II, is descended from the Army high-performance computing system "Mana", formerly located at the Maui HPC Center in Hawaii, and donated and physically moved to SMU through the efforts of ARO and SMU.