By Matthew Chin

What happens at tiny scales when an electrically charged hot gas hits new advanced materials? An interdisciplinary team of UCLA Engineers has won an $890,000 grant from the Air Force Office of Scientific Research (AFOSR) to explore this question. The grant amount is the largest distributed from the office this year.

Plasmas are gases comprised of electrically charged particles, electrons and ions, which are commonly used in electric propulsion systems for spacecraft. These electric thrusters use electromagnetic forces to accelerate ions to extremely high velocities to propel spacecraft at high efficiency.

A new generation of advanced microarchitectured materials could hold great promise for spacecraft, as well as many other applications. But more research is needed to understand how these materials and their boundaries respond in the presence of the ions and electrons in high temperature plasmas, simply put, how durable are they for these applications?

With funding from AFOSR, the UCLA Engineering team will construct a new high-power plasma source withhigh-precision diagnostic facility. Currently, materials bombarded by plasma are commonly examined after a long cool-down period with exposure to atmospheric conditions. The new UCLA Engineering facility will allow the researchers to use powerful diagnostics and microscopes to carefully analyze the materials as they are hit with ions and electrons inside a large vacuum chamber, at equivalent temperatures as high as  three  million Kelvin.  This will allow researchers to examine, at nano-scales, what happens to the structure and composition of the material surface, the plasma, and at the interface between the two.

The principal investigator on the grant is Richard Wirz, UCLA assistant professor of mechanical and aerospace engineering, a leader in plasma processes for advanced space propulsion systems. The project’s co-principal investigators are Nasr Ghoniem, UCLA professor of mechanical and aerospace engineering, a world expert in aerospace materials who has pioneered research and modeling in microarchitectured materials that are well-suited for demanding plasma applications; and Suneel Kodambaka, UCLA associate professor of materials science and engineering, an expert in the thermal, chemical, and mechanical characterization of materials and will provide important insight to the surface dynamics of the advanced materials that will be examined in this facility.

“This facility will provide a leap forward in space travel and communication by demonstrating materials that are ideal for long life and high power operation of electric thrusters and spacecraft communication systems,” Wirz said. “Such technologies will enable exciting space missions such as asteroids retrieval, and ambitious missions to other planets and their moons.”

Main Image: A preliminary build of the UCLA Plasma-Material Interactions facility. This picture shows the plasma column viewed through a 1-m diameter window of 2” thick plexiglass. The AFOSR grant will be used to build a version that can operate at high-power, in ultra-high vacuum, and with precision diagnostics.