Plasma Instabilities Observed

Whether between galaxies or within doughnut-shaped fusion devices known as tokamaks, the electrically charged fourth state of matter known as plasma regularly encounters powerful magnetic fields, changing shape and sloshing in space. 

Now, a new measurement technique using protons, subatomic particles that form the nuclei of atoms, has captured details of this sloshing for the first time, potentially providing insight into the formation of enormous plasma jets that stretch between the stars.

Scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) created detailed pictures of a magnetic field bending outward because of the pressure created by expanding plasma. 

As the plasma pushed on the magnetic field, bubbling and frothing known as magneto-Rayleigh Taylor instabilities arose at the boundaries, creating structures resembling columns and mushrooms.          READ MORE...

Innovative New Magnet

PPPL physicist Yuhu Zhai in front of a series of images related to his magnet research. 

Scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have designed a new type of magnet that could aid devices ranging from doughnut-shaped fusion facilities known as tokamaks to medical machines that create detailed pictures of the human body.

Tokamaks rely on a central electromagnet known as a solenoid to create electrical currents and magnetic fields that confine the plasma—the hot, charged state of matter composed of free electrons and atomic nuclei—so fusion reactions can occur. But after being exposed over time to energetic subatomic particles known as neutrons emanating from the plasma, insulation surrounding the electromagnet's wires can degrade. If they do, the magnet could fail and reduce a tokamak's ability to harness fusion power.

In this new type of magnet, metal acts as insulation and therefore would not be damaged by particles. In addition, it would operate at higher temperatures than current superconducting electromagnets do, making it easier to maintain.

Fusion, the power that drives the sun and stars, combines light elements in the form of plasma to generates massive amounts of energy. Scientists are seeking to replicate fusion on Earth for a virtually inexhaustible supply of power to generate electricity.

"Our innovation both simplifies the fabrication process and makes the magnet more tolerant of the radiation produced by the fusion reactions," said Yuhu Zhai, a principal engineer at PPPL and lead author of a paper reporting the results in Superconductor Science and Technology.  READ MORE...