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Based on the dispersion equation obtained from the Helmholtz equation in the plasma sheath region and main plasma column for surface waves, the propagation constant properties on the interface of the plasma sheath region and main plasma column region are studied. The analytic formula of propagation constant for the azimuthally symmetric surface wave (m=0 mode) and non-symmetric surface waves (m=1, 2, 3, and 4 modes) on the interface is presented, which indicates the effect of the thickness of the plasma sheath region on the propagation constant characteristics. The analytical result shows that the thickness has a significant influence on the propagation constant when the thickness is 0.01 times smaller than the thickness of the main plasma column region for both the symmetric and non-symmetric surface waves, while there is a significant difference in the propagation constant amplitude between the m=1 mode and other four modes. [ABSTRACT FROM AUTHOR]

Phase and attenuation properties of azimuthal symmetric surface waves are investigated analytically in an un-magnetized cylindrical plasma column based on the transcendental dispersion relation. A novel method of calculating the wave power deposition in terms of complex electric conductivity is proposed. Electron density distribution is obtained theoretically through charged particle balance theory. It is shown that the effect of the electron temperature on the dispersion curve can be neglected when kzα < 1. Both the phase/attenuation characteristics and wave energy deposition properties of the azimuthal symmetric surface wave have an evident dependence on the electron density and the electron collision frequency. [ABSTRACT FROM AUTHOR]

The structure of the drift-island surface of passing fast ions (PFIs) is investigated in the presence of the resonant interaction with a magnetic island. Two overlapping regions of the drift-island surface and the magnetic island surface are found, one corresponding to local overlapping region and the other to non-local one. Here, the word "nonlocal" denotes that the resonances in the core plasma can have effects on the PFIs near the plasma boundary, while the "local" represents that the PFIs just near the resonant location are influenced. The nonlocal overlapping constructs a transport path along which the PFIs can become losses. There are three kinds of drift-island surfaces to join in forming the transport paths. A pitch angle region, which is called pitch angle gap, is found near the plasma boundary, where the drift-island surface cannot be formed and few PFIs are lost. The pitch-angle selective features of PFI losses are obtained by analyzing the three kinds of drift-island surfaces. The coupling between the crowd drift island surfaces and the collision can induce the prompt losses of PFIs and rapidly slowing down of PFI energy. The time of the prompt losses and the slowing down rate are calculated. Qualitatively, the theoretical results are in well agreement with the experimental observations in ASDEX Upgrade [M. García-Muñoz et al., Nucl. Fusion 47, L10 (2007)]. [ABSTRACT FROM AUTHOR]

The enhanced transport of passing energetic ions (PEIs) in presence of the resonant interactions with a rotating magnetic island is investigated within the drift kinetic framework. When the island rotation plays a role in the resonant interaction, we find that the velocities of PEIs satisfy a constraint relation of resonant flux surface in phase space. The resonant flux surfaces overlap with the magnetic flux surfaces in real space. A new transport channel responsible for the PEIs moving across the magnetic flux surfaces, i.e., continuously overlapping, is found. Two kinds of radial motions can be induced by the surface overlapping: one arises from the coupling between the resonance and the collision with the background plasma and the other from not completely overlapping of the two surfaces. The two radial motions and the symmetry-breaking induced radial motion constitute the total radial motion. When the pitch-angle scattering rate is very weak, the surface-shear induced transport is dominant. Only a small increase in the collision rate can significantly influence the total transport. [ABSTRACT FROM AUTHOR]