The Ohio State University at Marion


​Professor Orban contributes to groundbreaking study on stellar plasmas


Ohio State Marion Assistant Professor of Physics, Chris Orban, Ph.D. contributed to a highly-awaited scientific study on stellar plasmas entitled “A higher-than-predicted measurement of iron opacity at solar interior temperatures” that was recently published in the journal Nature.

The study was led by staff scientist Dr. Jim Bailey of Sandia National Laboratory in Albuquerque, New Mexico.

The study is a careful analysis of the radiative properties of super-heated matter in an experiment conducted at the Sandia Z Machine, which is the largest experiment of its kind in the world. The tremendous electric discharge created by the Z Machine (see figure, to the right) produced x-rays that heated a sample of Iron to a multi-million degree temperature, similar to the conditions in the interior of the sun.

Once heated, x-ray data is recorded and later compared to quantum mechanical models for the transparency of iron at these temperatures. Surprisingly, the results strongly disagree with the predictions of the quantum mechanical models, suggesting that current models of the sun may not be as accurate as previously assumed.

Prof. Chris Orban contributed to this study alongside Columbus campus professor Anil Pradhan and Ohio State staff scientist Dr. Sultana Nahar. Prof. Orban advises three undergraduate students at Ohio State Marion and two Ph.D. students at the Columbus campus.

Lead author of the study, Dr. Jim Bailey, discusses the project with NPR

http://www.npr.org/2014/12/30/374033068/scientists-bring-the-sun-down-to-earth-to-learn-how-it-works

The study is available from the journal Nature (please visit OSU Marion library for access to Nature articles)

http://www.nature.com/nature/journal/v517/n7532/full/nature14048.html