Understanding mechanisms of electron-molecule collisions could help predict operations inside ITER fusion chamber

Jan 11, 2013
Understanding mechanisms of electron-molecule collisions could help predict operations inside ITER fusion chamber

An international team of physicists has calculated the efficiency of a reaction involving an incoming electron kicking out an electron from the metal beryllium (Be) or its hydrogen compound molecules, in an article about to be published in European Physical Journal D.

The efficiency, which partly depends on the electron's incoming speed, is encapsulated in a quantity referred to as electron-impact ionisation cross sections (EICS). Electron- matter because they occur in a broad range of applications from the simplest like fluorescent lamps to the most complex, for example, in ionised matter found in plasmas such as latest generation screens, the outer space of the universe, and in fusion reactors.

In the future prototype ITER, currently being built in southern France, beryllium comes into the plasma because it is one of the constituent materials of the fusion chamber walls. The walls get eroded on contact with hot leading to the formation of beryllium in gaseous form and beryllium hydrides, BeH and BeH2, present in various forms of electric charge and state.

Given this intrusion of beryllium in the hydrogen plasma, requires a knowledge of the EICS to predict and simulate its operations. The problem is that EICS are very difficult to calculate exactly. Instead, the authors relied on two approximation methods namely, the Deutsch-Märk (DM) and the Binary-Encounter-Bethe (BEB) method. These methods, albeit not new, have never before been applied to and its derivatives.

To use these models, the authors first collected the necessary input data obtained from quantum chemical calculations of characteristics such as orbital energies, kinetic energies and orbital populations. To facilitate use of their EICS by the ITER team, the authors eventually converted the numerical cross sections into equations used in simulation codes.

Explore further: The science of charismatic voices

More information: T. Maihom, I. Sukuba, R. Janev, K. Becker, T. Märk, A. Kaiser, J. Limtrakul, J. Urban, P. Mach and M. Probst (2013), Electron Impact Ionization Cross Sections of Beryllium and Beryllium Hydrides, European Physical Journal D, DOI 10.1140/epjd/e2012-30691-1

add to favorites email to friend print save as pdf

Related Stories

New jet results tick all the boxes for ITER

Oct 08, 2012

Latest results from the Joint European Torus (JET) fusion device are giving researchers increasing confidence in prospects for the next-generation ITER project, the international experiment that is expected ...

Wanted: the right wall material for ITER

Oct 12, 2007

ASDEX Upgrade at Max Planck Institute of Plasma Physics (IPP) in Garching, Germany, recently became the world's first and only device allowing experiments with a wall completely clad with metal, viz. tungsten. ...

Jaguar supercomputer harnesses heat for fusion energy

Apr 18, 2011

University of California-Irvine researcher Zhihong Lin is using the Jaguar supercomputer at Oak Ridge National Laboratory to study fusion reactions, which produce helium from hydrogen and release energy in ...

World's largest fusion device goes back to work

Sep 05, 2011

September is commonly the month where things begin to gather pace again, and in the world of fusion energy research, things are no different. European scientists working on the Joint European Torus (JET), ...

One step closer to controlling nuclear fusion

Jan 13, 2012

Using a heating system, physicists have succeeded for the first time in preventing the development of instabilities in an efficient alternative way relevant to a future nuclear fusion reactor. It’s an ...

Recommended for you

High-intensity sound waves may aid regenerative medicine

11 hours ago

Researchers at the University of Washington have developed a way to use sound to create cellular scaffolding for tissue engineering, a unique approach that could help overcome one of regenerative medicine's ...

Formula could shed light on global climate change

15 hours ago

Wright State University researchers have discovered a formula that accurately predicts the rate at which soil develops from the surface to the underlying rock, a breakthrough that could answer questions about ...

New world record for a neutron scattering magnet

16 hours ago

A unique magnet developed by the Florida State University-headquartered National High Magnetic Field Laboratory (MagLab) and Germany's Helmholtz Centre Berlin (HZB) has reached a new world record for a neutron ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.