It forms when a gas is supercharged with energy so that its atoms become ionized, meaning electrons are stripped from their atoms. In contrast, the plasmas used in the CSU study were created by first cooling atoms to temperatures just above absolute zero before converting them into plasma. He said the most difficult part of the work was how complicated the plasma system gets at low temperatures. Keeping that kind of plasma stable long enough to generate useful energy remains one of the biggest scientific and engineering challenges on the path to clean and limitless energy. “It is satisfying to have created the coldest measured electrons in a plasma formed in a lab right here at CSU.