Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 11
    Electronic Resource
    Electronic Resource
    Theory of kinetic ballooning modes excited by energetic particles in tokamaks (1993)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 3284-3290 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Resonant excitations of kinetic ballooning modes by the energetic ions/alpha particles in tokamaks have been analyzed theoretically. The theoretical analysis includes finite-size orbit effects of both circulating and trapped particles. With energetic particle contributions suppressed in the singular inertial layer, an analytic dispersion relation can then be derived via an asymptotic matching analysis. The dispersion relation, in particular, demonstrates the existence of two types of modes; that is, the magnetohydrodynamic gap mode and the energetic-particle continuum mode. Specific expressions for real frequencies, growth rates and threshold conditions are also derived for a model slowing-down beam ion distribution function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860624
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Gyrophase-coherent electron cyclotron maser (1988)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 31 (1988), S. 3120-3126 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The basic physics of an electron cyclotron maser driven by a coherently gyrophased, helical electron beam in a uniform magnetic field is analyzed. Theoretical predictions of gain enhancement and reduction in different regimes of the cyclotron instability, compared to a gyrotropic cyclotron maser, are verified with computer simulations. A physical explanation is presented for these findings. Beam-to-radiation energy conversion efficiency in the autoresonance regime is studied with computer simulations and compared with that for a gyrotropic beam.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866968
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Theory of semicollisional drift-interchange modes in cylindrical plasmas (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 2432-2438 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Resistive interchange instabilities in cylindrical plasmas are studied, including the effects of electron diamagnetic drift, perpendicular resistivity, and plasma compression. The analyses are pertinent to the semicollisional regime where the effective ion gyroradius is larger than the resistive layer width. Both analytical and numerical results show that the modes can be completely stabilized by the perpendicular plasma transport. Ion sound effects, meanwhile, are found to be negligible in the semicollisional regime.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865249
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Resistive ballooning modes in an axisymmetric toroidal plasma with long mean free path (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 2201-2208 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Tokamak devices normally operate at such high temperatures that the resistive fluid description is inappropriate. In particular, the collision frequency may be low enough for trapped particles to exist. However, on account of the high conductivity of such plasmas, one can identify two separate scale lengths when discussing resistive ballooning modes. By describing plasma motion on one of these, the connection length, in terms of kinetic theory the dynamics of trapped particles can be incorporated. On the resistive scale length, this leads to a description in terms of modified fluid equations in which trapped particle effects appear. The resulting equations are analyzed and the presence of trapped particles is found to modify the stability properties qualitatively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865272
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Theory of continuum damping of toroidal Alfvén eigenmodes in finite-β tokamaks (1993)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 3668-3690 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A general theoretical approach has been formulated for analyzing two-dimensional structures of high-n toroidal Alfvén eigenmodes (TAE) in large aspect-ratio, finite-β tokamaks. Here, n is the toroidal wave number and β is the ratio between plasma and magnetic pressures. The present approach generalizes the standard ballooning-mode formalism and is capable of treating eigenmodes with extended global radial structures, as well as finite coupling between discrete and continuous spectra. Employing the well-known (s,α) model equilibrium and assuming a linear equilibrium profile, the present approach has been applied to the calculation of the resonant continuum damping rate of TAE modes. Here, s and α denote, respectively, the strengths of magnetic shear and pressure gradients. In particular, it is found that there exists a critical α value, αc(s), such that, as α→αc, the continuum damping rate is significantly enhanced and, thus, could suppress the potential TAE instability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860839
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Kinetic theory of the ion-temperature-gradient-driven mode in the long wavelength limit (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2496-2505 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The stability of the ion-temperature-gradient-driven mode in the long wavelength limit is investigated by retaining the kinetic effects associated with the ion transit frequency. The complete trapped electron dynamics is also considered. The toroidal branch is weakly affected by the trapped electron dynamics while the slablike branch is more strongly affected by trapped electrons. The implications of these results for the understanding of the improved confinement regimes observed in the presence of peaked density profiles is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859960
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Linear theory of an electron cyclotron autoresonance maser with a "phase filter'' (1988)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 31 (1988), S. 3116-3119 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The linear growth rate of an electron cyclotron autoresonance maser (CARM) with a phase filter, constructed by imposing a transverse magnetostatic wiggler, is derived from relativistic kinetic theory. The theoretical results confirm previous findings from computer simulation showing substantial enhancement of the growth rate near the autoresonance condition. This theory provides an additional, more readily accessible tool for designing a novel phase filter-assisted CARM. The mathematical formalism developed to treat the complex electron motion in this device is introduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866967
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Theory of energetic trapped particle-induced resistive interchange-ballooning modes (1986)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 29 (1986), S. 2960-2974 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A theory describing the influence of energetic trapped particles on resistive-interchange-ballooning modes in tokamaks is presented. It is shown that a population of hot particles trapped in the region of adverse curvature can resonantly interact with and destabilize the resistive interchange mode, which is stable in their absence because of favorable average curvature. The mode is different from the usual resistive interchange mode not only in its destablization mechanism, but also in that it has a real component to its frequency comparable to the precessional drift frequency of the rapidly circulating energetic species. Corresponding growth rate and threshold conditions for this trapped-particle-driven instability are derived and finite banana width effects are shown to have a stabilizing effect on the mode. Finally, the ballooning/tearing dispersion relation is generalized to include hot particles, so that both the ideal and the resistive modes are derivable in the appropriate limits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865496
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Microinstabilities in weak density gradient tokamak systems (1986)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 29 (1986), S. 3715-3718 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A prominent characteristic of auxiliary-heated tokamak discharges which exhibit improved ("H-mode type'') confinement properties is that their density profiles tend to be much flatter over most of the plasma radius. Despite this favorable trend, it is emphasized here that, even in the limit of zero-density gradient, low-frequency microinstabilities can persist because of the nonzero temperature gradient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866014
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Theory of semicollisional kinetic Alfvén modes in sheared magnetic fields (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 3061-3065 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The spectra of the semicollisional kinetic Alfvén modes in a sheared slab geometry are investigated, including the effects of finite ion Larmor radius and diamagnetic drift frequencies. The eigenfrequencies of the damped modes are derived analytically via asymptotic analyses. In particular, as one reduces the resistivity, it is found that, because of finite ion Larmor radius effects, the damped mode frequencies asymptotically approach finite real values corresponding to the end points of the kinetic Alfvén continuum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865347
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...