S.E. Sharapov B. Alper H.L. Berk D.N. Borba B.N. Breizman C.D. Challis I.G.J. Classen E.M. Edlund J. Eriksson A. Fasoli E.D. Fredrickson Et Al
Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfven instabilities and modelling tools developed world-wide, and discusses progress in interpreting the observed phenomen…
PublishedJ. P. Graves I. Chapman S. Coda L.-G. Eriksson T. Johnson
The sawtooth control mechanism in plasmas employing off-axis toroidally propagating ion cyclotron resonance waves in tokamaks is reinvestigated. The radial drift excursion of energetic passing ions distributed asymmetrically in the velocity parallel to the magnetic field determines stability when the rational q 1/4 1 surface resides within a narrow…
PublishedS. E. Sharapov L.-G. Eriksson A. Fasoli G. Gorini J. Källne V. G. Kiptily A. A. Korotkov A. Murari S. D. Pinches D. S. Testa P. R. Thomas
Studies establishing key phenomena and developing diagnostics for energetic particle physics, which are essential for the next step burning plasma experiments such as the International Thermonuclear Experimental Reactor (ITER), have been performed at the Joint European Torus (JET). Experiments have demonstrated clear selfheating of deuterium-tritiu…
PublishedJ.-M. Noterdaeme L.-G. Eriksson M. Mantsinen M.-L. Mayoral D. Van Eester J. Mailloux C. Gormezano T. T. C. Jones
The physics studies of the three “heating” systems that are installed on JET are reviewed. Results from the beginning of JET up to now are presented with some emphasis on the more recent ones. The systems were used not only for heating, where JET has laid the groundwork to qualify them for heating the next generation of machines to ignition, bu…
PublishedW. Zwingmann M. Airaj L. Appel V. Drozdov L.-G. Eriksson B. Guillerminef G.T.A. Huysmans F. Imbeaux P. Mccarthy Ph. Moreau M. Romanelli P. Strand The Imp-1/Isip Team
The Integrated tokamak modelling taskforce was set up to provide the European scientific community with simulation tools for preparing and analysing discharges of fusion experiments. We will report on recent progress made on the taskforce project on equilibrium and linear stability. A generic data structure has been devised to describe the geometry…
PublishedH. Smith P. Helander L.-G. Eriksson D. Anderson M. Lisak F. Andersson
After the thermal quench of a tokamak disruption, the plasma current decays and is partly replaced by runaway electrons. A quantitative theory of this process is presented, where the evolution of the toroidal electric field and the plasma current is calculated self-consistently. In large tokamaks most runaways are produced by the secondary avalanch…
PublishedH. Smith P. Helander L.-G. Eriksson T. Fülöp
The usual calculation of Dreicer [Phys. Rev. 115 , 238 (1959); 117 , 329 (1960)] generation of runaway electrons assumes that the plasma is in a steady state. In a tokamak disruption this is not necessarily true since the plasma cools down quickly and the collision time for electrons at the runaway threshold energy can be comparable to the cooling …
PublishedP. Helander R. J. Akers L.-G. Eriksson
It is well known that when neutral beams inject ions into trapped orbits in a tokamak, the transfer of momentum between the beam and the plasma occurs through the torque exerted by a radial return current. It is shown that this implies that the angular momentum transferred to the plasma can be larger than the angular momentum of the beam, if the in…
PublishedL.-G. Eriksson P. Helander F. Andersson D. Anderson M. Lisak
Self-consistent modeling of the evolution of the plasma current during disruptions in large tokamaks is presented, taking into account both the generation of runaway electrons and their backreaction on the electric field. It is found that the current profile changes dramatically, so that the postdisruption current carried by runaway electrons is mu…
PublishedP. Helander H. Smith T. Fülöp L.-G. Eriksson
The distribution function of suprathermal electrons in a slowly cooling plasma is calculated by an asymptotic expansion in the cooling rate divided by the collision frequency. Since the collision frequency decreases with increasing velocity, a high-energy tail forms in the electron distribution function as the bulk population cools down. Under cert…
Published