[ skip to content ]

News @ ODU

Paper in Prestigious Physics Journal Spotlight's Research Pioneered by ODU's Laroussi

mlarouss-mounir-laroussi-1Mounir Laroussi

The prestigious academic journal Physics Reports has dedicated an entire issue to theory and applications of guided ionization waves in low temperature plasma jets, which were discovered in 2005 in the laboratory of Old Dominion University electrical engineer Mounir Laroussi.

Laroussi, director of the Laser & Plasma Engineering Institute of ODU's Frank Batten College of Engineering and Technology, is one of four authors of the article "Guided Ionization Waves: Theory and Experiments" in Physics Reports, one of the world's leading physics journals.

Laroussi's specialty is the plasma that can be created in regular atmospheric conditions and can be used in a variety of applications, such as dental or wound-healing treatments, that do not burn normal human tissue. Conventional plasma, like that present in lightning and in television sets, is created in the absence of atmospheric pressure and is radically hot.

Both plasmas have been shown to kill germs, but the low-temperature version has gotten more attention for biomedical applications because it is safer and easier to use. Laroussi said the discovery of guided ionization waves - or guided plasma streamers - turned out to be crucial for medical applications of plasma.

"Usually plasma streamers occur in a random fashion and branch out in several unpredictable directions. Guided streamers can be controlled to travel in a single direction and at predictable times. This way one can aim the plasma at a precise location of interest," he said.

Following the discovery of this phenomenon, groups around the world have engaged in studying it, producing about 100 peer reviewed research publications, essentially a whole research community formed around the topic. "We feel very fortunate and honored to have contributed new knowledge to field of plasma physics," Laroussi said.

Paper lead author Xinpei Lu, from China's HuaZhong University, was a post-doctoral student with Laroussi in 2005, when guided ionization waves - known as plasma bullets - were discovered. The paper's other authors are George Naidis, a leading plasma modeling and simulation expert from the Russian Academy of Sciences, and Ken Ostrikov, a world-leading expert on plasma and nanotechnology from Australia's Commonwealth Scientific and Industrial Research Organization.

Identified in the journal abstract as, "fundamental phenomena that occur upon application of sufficiently strong electric fields to gases," guided ionization waves are studied through numerous technological applications of electrical discharges.

The 43-page article reviews the work of those various research thrusts, discussing the fundamental physics of the guided streamer-like structures - plasma bullets which are produced in cold atmospheric-pressure plasma jets.

"This knowledge is very useful to optimize the efficacy of applications of plasma streamer discharges in various fields, ranging from health care and medicine to materials science and nanotechnology," the article abstract notes.

As part of his research into atmospheric plasma, Laroussi developed the plasma "pencil," a hand-held device that emits a stream of cool plasma. The miniature light saber has been featured in a broad array of popular media, including National Geographic, as well as professional publications. The articles have noted the germ-killing applications, and the ease of use, of the plasma pencil. In the past few years, the ODU professor of electrical and computer engineering has collaborated with life scientists at the university to study the way the so-called plasma that shoots from his hand-held pencil can kill diseased cells and bacteria.

Published by Elsevier, Physics Reports keeps the active physicist up-to-date on developments in a wide range of topics. Each report deals with one specific subject. These reviews are specialist in nature but contain enough introductory material to make the main points intelligible to a non-specialist. The reader will not only be able to distinguish important developments and trends, but also find a sufficient number of references to the original literature.