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Fusion energy: Progress, partnerships, and the path to deployment
Over the past decade, fusion energy has moved decisively from scientific aspiration toward a credible pathway to a new energy technology. Thanks to long-term federal support, we have significantly advanced our fundamental understanding of plasma physics—the behavior of the superheated gases at the heart of fusion devices. This knowledge will enable the creation and control of fusion fuel under conditions required for future power plants. Our progress is exemplified by breakthroughs at the National Ignition Facility and the Joint European Torus.
F. Castejón, J. M. Reynolds, J. M. Fontdecaba, R. Balbín, J. Guasp, D. López-Bruna, I. Campos, L. A. Fernández, D. Fernández-Fraile, V. Martín-Mayor, A. Tarancón
Fusion Science and Technology | Volume 50 | Number 3 | October 2006 | Pages 412-418
Technical Paper | Stellarators | doi.org/10.13182/FST06-A1263
Articles are hosted by Taylor and Francis Online.
It was observed previously that the ion temperature profile of low-density electron cyclotron resonance-heated TJ-II plasmas is almost flat and that energetic ions are present well outside the last closed magnetic surface. The heat diffusivity obtained for such ion temperature profiles is very high, and therefore, transport cannot be described by Fick's law. In this work, ion trajectories with different pitches and starting points have been calculated for the relevant magnetic configuration. It is found that a feasible explanation for such a flat mean energy profile is that ion orbits are wide enough to communicate distant parts of the plasma radius, thus giving an effective flat ion temperature profile, for these low-density (<1019-m-3) plasmas. The distribution function is also obtained without considering collisions; thus, non-Maxwellian features are found. The final particle density shows inhomogeneities on a magnetic surface.