J. Greenhough S.C. Chapman S. Chaty R.O. Dendy G. Rowlands
Whilst direct observations of internal transport in accretion disks are not yet possible, measurement of the energy emitted from accreting astrophysical systems can provide useful information on the physical mechanisms at work. Here we examine the unbroken multi-year time variation of the total X-ray flux from three sources: Cygnus X-1, the microqu…
PublishedM. J. Mantsinen L.C. Ingesson T. Johnson V.G. Kiptily M.-L. Mayoral S. E. Sharapov B. Alper L. Bertalot S. Conroy L.-G. Eriksson T. Hellsten J.-M. Noterdaeme S. Popovichev E. Righi A. A. Tuccillo
Experiments on the JET tokamak show that the wave-induced pinch in the presence of toroidally asymmetric waves can provide a tool for controlling the profile of ion-cyclotron-resonant 3 He ions. Direct evidence for the wave-induced pinch has been obtained from the measured -ray emission profiles. Concurrent differences in the excitation of Alfve?n …
PublishedA. Thyagaraja N.L Oureiro P.J. Knight
Advection–diffusion equations occur in a wide variety of fields in many contexts of active and passive transport in fluids and plasmas. The effects of sheared advective flows in the presence of irreversible processes such as diffusion and viscosity are of considerable current interest in tokamak and astrophysical contexts, where they are thought …
PublishedT. Fülöp P. Helander Peter J. Catto
Neutral atoms in the tokamak edge affect the electric field and plasma flow through charge exchange. Here, it is shown that these effects depend sensitively on the poloidal location of the atoms. It is found that the radial electric field and toroidal flow velocity in a collisional edge plasma are largest if the atoms are concentrated on the inboar…
PublishedH. R. Wilson P. B. Snyder G. T. A. Huysmans R. L. Miller
A new computational tool, edge localized instabilities in tokamaks equilibria (ELITE), has been developed to help our understanding of short wavelength instabilities close to the edge of tokamak plasmas. Such instabilities may be responsible for the edge localized modes observed in high confinement H-mode regimes, which are a serious concern for ne…
PublishedP. Helander L.-G. Eriksson R. J. Akers C. Byrom C.G. Gimblett M. R. Tournianski
Spontaneous acceleration of ions to suprathermal energies is observed during magnetic reconnection in the Mega-Ampere Spherical Tokamak (MAST). A high-energy tail is observed in the iondistribution function following each internal reconnection event in Ohmic discharges. This phenomenon is explained in terms of runaway ion acceleration in the electr…
PublishedT. Johnson T. Hellsten M. Mantsinen V. Kiptily S. Sharapov et al.
The RF-induced pinch of 3 He minority ions has been observed in JET affecting the diamagnetic energy, the fast ion energy content, the sawtooth period, the Alfvén eigenmode excitation and the y-emission. Further, the y-emission is consistent with RF-detrapping into co-current passing orbits. The results from the SELFO code are consistent with the …
PublishedF. Andersson P. Helander L.-G. Eriksson
Relativistic electrons emit synchrotron radiation due to their gyro- and guiding-center motions in a curved magnetic field. In this article, the kinetic theory of relativistic electron beams is developed to account for radiation reaction by including the Abraham–Lorentz reaction force in the kinetic equation. As an application of this theory, the…
PublishedV. Pericoli Ridolfini S. Podda J. Mailloux Y. Sarazin Y. Baranov et al.
Good coupling of the LH power during the whole internal transport barrier (ITB) phase has been achieved in JET by fitting the plasma shape to the LH antenna shape and by injecting CD 4 gas from a pipe near to the LH grill. No adverse effect on the edge pedestal or on the ITB quality, or significant impurity influx is observed. The key is the low io…
PublishedS. C. Chapman R.O. Dendy B. Hnat
Confinement phenomenology characteristic of magnetically confined plasmas emerges naturally from a simple sandpile algorithm when the parameter controlling redistribution scale length is varied. Close analogs are found for enhanced confinement, edge pedestals, and edge localized modes (ELMs), and for the qualitative correlations between them. These…
Published