10-foot diameter Big Red Plasma Ball

Physics Professor Cary Forest stands next to the 10-foot-diameter Big Red Plasma Ball, which mimics astrophysical and solar plasmas at temperatures of 500,000 degrees Fahrenheit. The aluminum interior of the structure was created in Portage, Wis. 


In a lab tucked inside Sterling Hall is the Big Red Plasma Ball – a device my team recently built to provide a window into plasmas like those that compose stars and our own sun.

We use the Big Red Plasma Ball – a carefully designed 10-foot diameter aluminum sphere lined with 3,000 powerful magnets – to mimic astrophysical and solar plasmas at lab temperatures of 500,000 degrees Fahrenheit.

Our experiments are inspired by the physics of stars, the plasma around black holes and the explosive plasmas created by solar flares and supernovae.

Researchers from around the world have trekked to the lab to conduct plasma research. Why is that knowledge so important?

The plasma state – the fourth and most energetic state of matter – is responsible for exposing us to the universe. Ninety-nine percent of the light we can detect with modern telescopes comes from plasma.

The Earth is one of the rare places in the universe where matter is found in solid, liquid and gas states; once we venture beyond the atmosphere we find that space is not empty but filled with dynamic and potentially dangerous plasma.

This makes understanding the physics of plasmas essential for mankind’s exploration of our local solar system as well as interpreting the beautiful images NASA and National Science Foundation instruments now send to us.

Plasmas are also technologically useful. All electronics, including cell phone and computer, are filled with parts created in plasma reactors.

Plasmas are now used to manufacture new materials like carbon nanotubes and even anti-matter. Plasmas are now routinely used biological applications like wound sterilization.

If mankind can learn to control on Earth the hot and dense thermonuclear plasmas like those found in stars, plasmas may ultimately provide a carbon-free and nearly endless supply of energy needed to sustain civilization through nuclear fusion energy.

Along my career path, I was fortunate enough to be mentored by Noah Hershkowitz, a UW-Madison plasma physicist.

Returning to Wisconsin as a faculty member after stints on the east and west coasts was an easy choice, not because I was returning home, but because UW-Madison provided the best research support of the three universities that were recruiting me. The university is one of the top institutions in plasma physics worldwide.

I now employ undergraduates and graduate students in much the same way that I was mentored early on. These students begin much like the sorcerer’s apprentice, figuratively sweeping floors and carrying water, but eventually get to satisfy their curiosity by making plasmas and measuring their properties.

For me, plasma physics is a discipline that is intrinsically interesting but also has tremendously important applications.

It allows me to contribute culturally to humankind through curiosity-driven research, understanding the beautiful light shows that nature shows us – solar flares, lightning, auroras and even campfires – and to contribute to civilization by helping to develop plasma technologies that include eventually building a star on earth to produce energy.