Advances in understanding turbulence and confinement in fusion energy research
Abstract
We briefly review advances during the past several years in both computer simulations of turbulence and experimental studies of confinement scalings. The International H-Mode Confinement Database Group has expanded the database, reducing (but not eliminating) uncertainties from tokamak-to-tokamak systematic variations that affected earlier extrapolations to reactor scales. Several tokamaks have reported that confinement can be improved with strong plasma shaping. Raising the plasma triangularity helps to raise the Greenwald density limit and reduce the machine size (with a side benefit of reducing the power loads on the divertors), reducing the risk of low performance from operating above the Greenwald density. Recent designs for a next step fusion device have incorporated such improvements; the proposed FIRE design uses them to the greatest extent. FIRE also takes advantage of the higher magnetic field possible with cryogenic CuBe coils, further reducing the size and cost of a next step device while maintaining comparable performance to other designs. On the more fundamental computational front, simulations done by the Plasma Microturbulence Project have made impressive contributions on both the theoretical side (such as showing the importance of very small electron-scale turbulence and identifying the crucial roles of secondary instabilities in controlling nonlinear saturation levels), and on the experimental side (by doing some detailed comparisons with experimental results).
- Publication:
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APS April Meeting Abstracts
- Pub Date:
- April 2003
- Bibcode:
- 2003APS..APRC10008H