Reply To: Investment risk

[Rezwan]

Yep. Pesky filters.

Separately, papers on plasma islands were beginning to surface in scientific circles. French physicist Paul-Henri Rebut described radiation-driven islands in a mid-1980s conference paper, but not in a periodical. German physicist Wolfgang Suttrop speculated a decade later that the islands were associated with the density limit. “The paper he wrote was actually the trigger for our idea, but he didn’t relate the islands directly to the Greenwald limit,” said Gates, who had worked with Suttrop on a tokamak experiment at the Max Planck Institute for Plasma Physics in Garching, Germany, in 1996 before joining PPPL the following year.

Why hadn’t researchers pieced together a similar theory of the density-limit puzzle before? The answer, says Gates, lies in how ideas percolate through the scientific community. “The radiation-driven islands idea never got a lot of press,” he says. “People thought of them as curiosities. The way we disseminate information is through publications, and this idea had a weak initial push.”

But a lot of this story is also about how individual scientists meet and talk face to face or email and call each other personally. Gets back to relationships.

In early 2011, the topic of plasma islands had mostly receded from Gates’ mind. But a talk by Delgado-Aparicio about the possibility of such islands erupting in the plasmas contained within the Alcator C-Mod tokamak reignited his interest. Delgado-Aparicio spoke of corkscrew-shaped phenomena called snakes that had first been been observed by PPPL scientists in the 1980s and initially reported by German physicist Arthur Weller.

Intrigued by the talk, Gates urged Delgado-Aparicio to read the papers on islands by Rebut and Suttrop. An email from Delgado-Aparicio landed in Gates’ in-box some eight months later. In it was a paper that described the behavior of snakes in a way that fit nicely with the C-Mod data. “I said, ‘Wow! He’s made a lot of progress,’” Gates remembers. “I said, ‘You should come down and talk about this.’”