Laser empties atoms from the inside out

March 25, 2013

An international team of plasma physicists has used one of the world's most powerful lasers to create highly unusual plasma composed of hollow atoms.

The experimental work led by scientists from the University of York, UK and the Joint Institute for High Temperatures of demonstrated that it is possible to remove the two most deeply bound electrons from atoms, emptying the inner most quantum shell and leading to a distinctive .

The experiment was carried out using the at the Central Facility at the Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory to further understanding of generation, which employs plasmas that are hotter than the core of the Sun.

The results are reported in the journal Physical Review Letters.

A hollow atom occurs when an electron buried in an atom is removed, usually by being hit by another electron, creating a hole while leaving all the other electrons attached. This process creates plasma, a form of ionised gas. An X-ray is released when the hole is filled.

Normally the process involves removing electrons from the outer shells of atoms first and working inwards. The team of scientists demonstrated a new mechanism for creating hollow atoms that involved emptying atoms from the inside out.

The experimental work used an intense laser, which at one petawatt delivers approximately 10,000 times the entire UK national grid, delivered in a thousand-billionth of a second, onto an area smaller than the end of a human hair.

Dr Nigel Woolsey, from the York Plasma Institute, Department of Physics, at the University of York was the Principal Investigator for the experimental work.

Dr Woolsey said: "At such extraordinary intensities electrons move at close to the speed of light and as they move they create perhaps the most intense ever observed on Earth. These X-rays empty the atoms from the inside out; a most extraordinary observation and one that suggests the physics of these interactions is likely to change, as lasers become more powerful."

Analysis and theoretical work was led by the Los Alamos National Laboratory, USA and Osaka University, Japan.

The analysis showed the mechanism for hollow atom generation was not due to the collision of electrons or driven by the laser photons, but was driven by the resulting radiation field from the interaction.

Lead author Dr James Colgan, from the Los Alamos National Laboratory, said: "The conditions under which the hollow atoms were produced were highly non-equilibrium and the production mechanism was quite surprising. These results indicate that a little-explored region of physics is now starting to become accessible with the unprecedented intensities reached by the world's leading laser facilities."

Co-author Dr Alexei Zhidkov, from Osaka University, said: "This experiment has demonstrated a situation where X-ray radiation dominates the atomic physics in a laser-plasma interaction; this indicates the importance of X-ray radiation generation in our physics description. Future experiments are likely to show yet more dramatic effects which will have substantial implications for diverse fields such as laboratory-based astrophysics."

If the scientific and technological challenges can be overcome, fusion offers the potential for an effectively limitless supply of safe, environmentally friendly energy. The experimental work was designed to further scientists understanding of how intense lasers can create electron beams with speeds close to the speed of light, then use these beams to heat fusion fuel to thermonuclear temperatures.

Co-author Dr Sergey Pikuz, from the Joint Institute for RAS, said: "The measurements, simulations, and developing physics picture are consistent with a scenario in which high-intensity laser technology can be used to generate extremely intense X-ray fields. This demonstrates the potential to study properties of matter under the impact of intense X-ray radiation."

Co-author Rachel Dance, a University of York PhD physics student, said: "This was a very dynamic experiment which led to an unexpected outcome and new physics. The hollow atom diagnostic was set to measure the hot electron beam current generated by the laser, and the results that came out of this in the end, showed us that the mechanism for hollow atom generation, was not collisional or driven by the laser photons, but by the resulting radiation field from the interaction."

Explore further: Billard game in an atom: Physicists trace the double ionization of argon atoms on attosecond time scales

More information: J Colgan et al. 'Exotic Dense-Matter States Pumped by a Relativistic Laser Plasma in the Radiation-Dominated Regime' appears in the current issue of the journal Physical Review Letters.

Related Stories

Unpeeling atoms and molecules from the inside out

June 30, 2010

( -- The first published scientific results from the world's most powerful hard X-ray laser, located at the Department of Energy's SLAC National Accelerator Laboratory, show its unique ability to control the behaviors ...

Measuring individual atoms with compact X-ray lasers

November 30, 2012

To look at small objects typically requires big machines. For example, the study of single atoms with a laser requires x-ray radiation of such high energy that it is only produced by accelerating electrons in large facilities. ...

Laser research shows promise for cancer treatment

August 21, 2012

( -- Scientists at Los Alamos National Laboratory have observed for the first time how a laser penetrates dense, electron-rich plasma to generate ions. The process has applications for developing next generation ...

Electron self-injection into an evolving plasma bubble

November 2, 2009

Particle accelerators are among the largest and most expensive scientific instruments. Thirty years ago, theorists John Dawson and Toshiki Tajima proposed an idea for making them thousands of times smaller: surf the particles ...

Recommended for you

Two teams independently test Tomonaga–Luttinger theory

October 20, 2017

(—Two teams of researchers working independently of one another have found ways to test aspects of the Tomonaga–Luttinger theory that describes interacting quantum particles in 1-D ensembles in a Tomonaga–Luttinger ...

Using optical chaos to control the momentum of light

October 19, 2017

Integrated photonic circuits, which rely on light rather than electrons to move information, promise to revolutionize communications, sensing and data processing. But controlling and moving light poses serious challenges. ...

Black butterfly wings offer a model for better solar cells

October 19, 2017

(—A team of researchers with California Institute of Technology and the Karlsruh Institute of Technology has improved the efficiency of thin film solar cells by mimicking the architecture of rose butterfly wings. ...

Terahertz spectroscopy goes nano

October 19, 2017

Brown University researchers have demonstrated a way to bring a powerful form of spectroscopy—a technique used to study a wide variety of materials—into the nano-world.


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Mar 25, 2013
I guess it is safe to assume the 'inside out' part refers only to the electrons, not the nucleon itself, I don't think they are talking about neutrons being ejected or protons.
1 / 5 (1) Mar 25, 2013
Excellent study. Very useful on several levels, especially if we can pinpoint a mechanism in space that effects these atoms in the same way near sources of X-ray generation. (coronal heating comes to mind)
5 / 5 (2) Mar 25, 2013
I guess it is safe to assume the 'inside out' part refers only to the electrons, not the nucleon itself, I don't think they are talking about neutrons being ejected or protons.

Just read the article. It says so quite plainly in one of the first paragraphs.

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.