3/28/2023 0 Comments Plasma particlesThe simulation (b) was in good qualitative agreement with the measured flows (a) as shown in the figure below (lefts side, the measured flow and right side the modeled counter part).ĭetailed analysis of the EMC3-EIRENE results and development of a 1-D model along the magnetic field lines enabled to identify the key physics driving this phenomenon. PhD Student Ian Waters carried out a series of simulations using the EMC3-EIRENE code to investigate unique Scrape-Off-Layer flow structures that were measured at the MAST tokamak. ![]() But I am charging ahead and aiming to apply the algorithm we've developed to new plasma physics problems.Full 3-D modeling of plasma edge transport and the interaction with the neutral particles around this edge plasma revealed the impact of localized neutral sources on the plasma flow pattern. "It drops several terms that will be important to include. "The algorithm we developed is for a simplified model," Zhang said. Qin next handed the problem to graduate student Fu, who put together a clever mathematical proof of the correctness of the algorithm that could become a step to further solutions. "So I ran a bunch of simulations and did all kinds of numerical experiments that showed the algorithm worked better than the classic algorithm that failed to conserve energy." However, the alternative method could not be proven theoretically. " I'm an experimentalist at heart and my approach to problems is to try it," she said. He thus devised an alternative method, an explicitly solvable algorithm that conserves the energy of the particles, which Zhang went on to try. "If an algorithm that simulates the process does not conserve the energy of the particles, the simulation cannot be trusted," he said. Just as the energy of an orbit does not change, "you want an algorithm that conserves the energy of the scattered plasma particles," she said.Ĭonserving that energy is critical, said Qin, whom Zhang consulted. Such scattering is often observed in fusion plasma when electrons collide with ions that are roughly 2,000-times heavier in collisions akin to ping-pong balls bouncing off basketballs.įor Zhang, the problem "was similar to trying to simulate the orbit of a planet," she recalled. She used a classic algorithm that failed to conserve energy during what is called the pitch-angle scattering process of particles colliding. When Zhang first tried simulating the fast particles she ran into a problem. Our simulations are all part of understanding how these particles behave." Sometimes they create plasma instabilities and sometimes they reduce them. "They can heat and drive current in the plasma. ![]() "We use them to do all sorts of things," Zhang said. Neutral beams play many roles when broken down into fast plasma particles. "We care about this because we want to understand how these fast particles influence the plasma," Zhang said. The particles could, for example, stem from the injection of high-energy neutral beams that are broken down, or "ionized" in the plasma and collide with the main plasma particles. The new PPPL algorithm helps track fast charged particles in the plasma. Scientists around the world are seeking to produce controlled fusion on Earth as an ideal source for generating electricity. Qin and Fu coauthored the paper.įusion powers the sun and stars by combining light elements in the form of plasma - the state of matter composed of free electrons and atomic nuclei, or ions, that makes up 99 percent of the visible universe - to release massive amounts of energy. He and Yichen Fu, a theoretical graduate student whom he advises, collaborated on the algorithm with Laura Xin Zhang, an experimental graduate student and lead author of a paper that reports the research in the journal Physical Review E. ![]() "This is a success story about close interaction between theorists and experimentalists that shows what can be done," said Hong Qin, a principal theoretical physicist at PPPL.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |