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| 2. |
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| 3. |
- Bingham, Robert, et al.
(författare)
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Solar coronal heating by plasma waves
- 2010
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Ingår i: Journal of Plasma Physics. - Cambridge university. - 0022-3778. ; 76:2, s. 135-158
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Tidskriftsartikel (refereegranskat)abstract
- The solar coronal plasma is maintained at temperatures of millions of degrees, much hotter than the photosphere, which is at a temperature of just 6000 K. In this paper, the plasma particle heating based on the kinetic theory of wave–particle interactions involving kinetic Alfvén waves and lower-hybrid drift modes is presented. The solar coronal plasma is collisionless and therefore the heating must rely on turbulent wave heating models, such as lower-hybrid drift models at reconnection sites or the kinetic Alfvén waves. These turbulent wave modes are created by a variety of instabilities driven from below. The transition region at altitudes of about 2000 km is an important boundary chromosphere, since it separates the collision-dominated photosphere/chromosphere and the collisionless corona. The collisionless plasma of the corona is ideal for supporting kinetic wave–plasma interactions. Wave–particle interactions lead to anisotropic non-Maxwellian plasma distribution functions, which may be investigated by using spectral analysis procedures being developed at the present time.
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| 4. |
- Brodin, Gert, et al.
(författare)
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A new decay channel for compressional Alfven waves in plasmas
- 2008
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Ingår i: Journal of Plasma Physics. - 0022-3778. ; 74:1, s. 99-105
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Tidskriftsartikel (refereegranskat)abstract
- We present a new efficient wave decay channel involving nonlinear interactions between a compressional Alfv´en wave, a kinetic Alfv´en wave, and a modified ion sound wave in a magnetized plasma. It is found that the wave coupling strength of the ideal magnetohydrodynamic (MHD) theory is much increased when the effects due to the Hall current are included in a Hall–MHD description of wave–wave interactions. In particular, with a compressional Alfv´en pump wave well described by the ideal MHD theory, we find that the growth rate is very high when the decay products have wavelengths of the order of the ion thermal gyroradius or shorter, in which case they must be described by the Hall–MHD equations. The significance of our results to the heating of space and laboratory plasmas as well as for the Solar corona and interstellar media are highlighted.
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| 5. |
- Brodin, Gert, et al.
(författare)
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Anomalous reflection and excitation of surface waves in metamaterials
- 2007
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Ingår i: Physics Letters A. - 0375-9601. ; 367:3, s. 233-236
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Tidskriftsartikel (refereegranskat)abstract
- We consider reflection of electromagnetic waves from layered structures with various dielectric and magnetic properties, including metamaterials. Assuming periodic variations in the permittivity, we find that the reflection is in general anomalous. In particular, we note that the specular reflection vanishes and that the incident energy is totally reflected in the backward direction, when the conditions for resonant excitation of leaking surface waves are fulfilled.
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| 6. |
- Brodin, Gert, et al.
(författare)
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Dispersion relation for electromagnetic wave propagation in a strongly magnetized plasma
- 2006
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Ingår i: New Journal of Physics. - Bristol, UK : Institute of Physics Pub.. - 1367-2630. ; 8:January, s. 16
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Tidskriftsartikel (refereegranskat)abstract
- A dispersion relation for electromagnetic wave propagation in a strongly magnetized cold plasma is deduced, taking photon–photon scattering into account. It is shown that the combined plasma and quantum electrodynamic effect is important for understanding the mode-structures in magnetar and pulsar atmospheres. The implications of our results are discussed.
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| 7. |
- Brodin, Gert, et al.
(författare)
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Kinetic and quantum electrodynamical theory for circularly polarized waves in a plasma
- 2007
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Ingår i: Physics Letters A. ; 371, s. 462
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Tidskriftsartikel (refereegranskat)abstract
- The theory for large amplitude circularly polarized waves propagating along an external magnetic field is further developed. Relativistic effects, quantum electrodynamical effects due to vacuum polarization and magnetization, as well as kinetic effects are included in our formalism. A general dispersion relation, which unites previous results, is derived. As a specific example, a low-frequency kinetic mode with a detailed dependence on the electron distribution function is studied.
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| 8. |
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| 9. |
- Brodin, Gert, et al.
(författare)
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Nonlinear interactions between three inertial Alfvén waves
- 2007
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Ingår i: Journal of Plasma Physics. - 0022-3778. ; 73:1, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- The resonant coupling between Alfvén waves is reconsidered. New results are found for cold agnetoplasmas where temperature effects are negligible.
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| 10. |
- Brodin, G, et al.
(författare)
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On the parametric decay of waves in magnetized plasmas
- 2009
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Ingår i: Journal of Plasma Physics. - Cambridge University Press. - 0022-3778. ; 75, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- We reconsider the theory for three-wave interactions in cold plasmas. In particular, we demonstrate that previously overlooked formulations of the general theory are highly useful when deriving concrete expressions for specific cases. We also point out that many previous results deduced directly from the basic plasma equations contain inappropriate approximations leading to unphysical results. Finally, generalizations to more elaborate plasma models containing, for example, kinetic effects are given.
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