Journal articles: 'Magnetic Islands'

1

Grosche, F. Malte. "Magnetic islands." Nature Physics 10, no. 2 (January 31, 2014): 94–95. http://dx.doi.org/10.1038/nphys2884.

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Shen, Chih Long, Po Cheng Kuo, G. P. Lin, Y. S. Li, Sin Liang Ou, and S. C. Chen. "Effect of Thicknesses on the Microstructure and Magnetic Properties of CoPt Thin Films." Advanced Materials Research 123-125 (August 2010): 655–58. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.655.

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The microstructures and magnetic properties of CoPt thin films with thicknesses between 1 and 20 nm deposited on amorphous glass substrate and post-annealing at 600°C for 30 min were investigated. The morphology of CoPt thin film would change from a discontinuous nano-size CoPt islands into a continuous film gradually as the film thickness was increased from 1 to 20 nm. The formation mechanism of the CoPt islands may be due to the surface energy difference between the glass substrate and CoPt alloy. Each CoPt island could be a single domain particle. This discontinuous nano-island CoPt recording film may increase the recording density and enhance the signal to noise ratio while comparing with the continuous film. The as-deposited 5 nm CoPt film revealed the separated islands morphology after annealing at 600°C for 30 min. This nano-size CoPt thin film may be a candidate for ultra-high density magnetic recording media due to its discontinuous islanded nanostructure.

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Schouteden, K., D. A. Muzychenko, and C. Van Haesendonck. "Spin-Polarized Scanning Tunneling Spectroscopy of Self-Organized Nanoscale Co Islands on Au(111) Surfaces." Journal of Nanoscience and Nanotechnology 8, no. 7 (July 1, 2008): 3616–20. http://dx.doi.org/10.1166/jnn.2008.412.

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Magnetic monolayer and bilayer Co islands of only a few nanometer in size were grown by atomic deposition on atomically flat Au(111) films. The islands were studied in situ by scanning tunneling microscopy (STM) and spectroscopy at low temperatures. Spin-resolved tunneling spectroscopy, using an STM tip with a magnetic coating, revealed that the Co islands exhibit a net magnetization perpendicular to the substrate surface due to the presence of spin-polarized d-states. A random distribution of islands with either upward or downward pointing magnetization was observed, without any specific correlation of magnetization orientation with island size or island height.

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Xia, Q., and V. Zharkova. "Particle acceleration in coalescent and squashed magnetic islands." Astronomy & Astrophysics 635 (March 2020): A116. http://dx.doi.org/10.1051/0004-6361/201936420.

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Aims. Particles are known to have efficient acceleration in reconnecting current sheets with multiple magnetic islands that are formed during a reconnection process. Using the test-particle approach, the recent investigation of particle dynamics in 3D magnetic islands, or current sheets with multiple X- and O-null points revealed that the particle energy gains are higher in squashed magnetic islands than in coalescent ones. However, this approach did not factor in the ambient plasma feedback to the presence of accelerated particles, which affects their distributions within the acceleration region. Methods. In the current paper, we use the particle-in-cell (PIC) approach to investigate further particle acceleration in 3D Harris-type reconnecting current sheets with coalescent (merging) and squashed (contracting) magnetic islands with different magnetic field topologies, ambient densities ranging between 108 − 1012 m−3, proton-to-electron mass ratios, and island aspect ratios. Results. In current sheets with single or multiple X-nullpoints, accelerated particles of opposite charges are separated and ejected into the opposite semiplanes from the current sheet midplane, generating a strong polarisation electric field across a current sheet. Particles of the same charge form two populations: transit and bounced particles, each with very different energy and asymmetric pitch-angle distributions, which can be distinguished from observations. In some cases, the difference in energy gains by transit and bounced particles leads to turbulence generated by Buneman instability. In magnetic island topology, the different reconnection electric fields in squashed and coalescent islands impose different particle drift motions. This makes particle acceleration more efficient in squashed magnetic islands than in coalescent ones. The spectral indices of electron energy spectra are ∼ − 4.2 for coalescent and ∼ − 4.0 for squashed islands, which are lower than reported from the test-particle approach. The particles accelerated in magnetic islands are found trapped in the midplane of squashed islands, and shifted as clouds towards the X-nullpoints in coalescent ones. Conclusions. In reconnecting current sheets with multiple X- and O-nullpoints, particles are found accelerated on a much shorter spatial scale and gaining higher energies than near a single X-nullpoint. The distinct density and pitch-angle distributions of particles with high and low energy detected with the PIC approach can help to distinguish the observational features of accelerated particles.

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MIKHAILOVSKII, A. B., S. V. KONOVALOV, G. I. SURAMLISHVILI, and V. S. TSYPIN. "Regularization of superdrift magnetic islands for finite electron temperature." Journal of Plasma Physics 67, no. 2-3 (April 2002): 99–114. http://dx.doi.org/10.1017/s0022377801001532.

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The regularization of magnetic islands is studied for the case when the electron temperature is larger than the ion temperature. The slab approximation is used. Drift effects are neglected, i.e., the case of superdrift magnetic islands, SDMIs, is analyzed. Then the regularization problem reduces to, first, a spreading of the step-functional velocity profile and the conventional delta-functional polarization current profile in the region near the island separatrix; second, finding the dispersion terms of the polarization current in this region; and, third, calculating the total polarization current contribution to the generalized Rutherford equation for the island width. It is shown that this problem can be solved if one allows for the effects of the electron pressure gradient in the parallel Ohm's law. The polarization current contribution in the case of islands regularized due to these effects proves to be the same as that in the case of nonregularized islands.

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Xia, Q., and V. Zharkova. "Particle acceleration in coalescent and squashed magnetic islands." Astronomy & Astrophysics 620 (December 2018): A121. http://dx.doi.org/10.1051/0004-6361/201833599.

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Aims. Magnetic reconnection in large Harris-type reconnecting current sheets (RCSs) with a single X-nullpoint often leads to the occurrence of magnetic islands with multiple O- and X-nullpoints. Over time these magnetic islands become squashed, or coalescent with two islands merging, as has been observed indirectly during coronal mass ejection and by in-situ observations in the heliosphere and magnetotail. These points emphasise the importance of understanding the basic energising processes of ambient particles dragged into current sheets with magnetic islands of different configuration. Methods. Trajectories of protons and electrons accelerated by a reconnection electric field are investigated using a test particle approach in RCSs with different 3D magnetic field topologies defined analytically for multiple X- and O-nullpoints. Trajectories, densities, and energy distributions are explored for 106 thermal particles dragged into the current sheets from different sides and distances. Results. This study confirms that protons and electrons accelerated in magnetic islands in the presence of a strong guiding field are ejected from a current sheet into the opposite semiplanes with respect to the midplane. Particles are found to escape O-nullpoints only through the neighbouring X-nullpoints along (not across) the midplane following the separation law for electrons and protons in a given magnetic topology. Particles gain energy either inside O-nullpoints or in the vicinity of X-nullpoints that often leads to electron clouds formed about the X-nullpoint between the O-nullpoints. Electrons are shown to be able to gain sub-relativistic energies in a single magnetic island. Energy spectra of accelerated particles are close to power laws with spectral indices varying from 1.1 to 2.4. The more squashed the islands the larger the difference between the energy gains by transit and bounced particles, which leads to their energy spectra having double maxima that gives rise to fast-growing turbulence. Conclusions. Particles are shown to gain the most energy in multiple X-nullpoints between O-nullpoints (or magnetic islands). This leads to the formation of electron clouds between magnetic islands. Particle energy gains are much larger in squashed islands than in coalescent ones. In summary, particle acceleration by a reconnection electric field in magnetic islands is much more effective than in an RCS with a single X-nullpoint.

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7

Davidson, MG, RL Dewar, HJ Gardner, and J. Howard. "Hamiltonian Maps for Heliac Magnetic Islands." Australian Journal of Physics 48, no. 5 (1995): 871. http://dx.doi.org/10.1071/ph950871.

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Magnetic islands in toroidal heliac stellarator vacuum fields are explored with Hamiltonian chaos theory and the associated area-preserving maps. Magnetic field line island chains are examined first analytically, with perturbation theory, and then numerically to produce Poincaré sections, which are compared with H−1 Heliac stellarator puncture plot diagrams. Rotational transform profiles are chosen to permit the comparison of twist map and nontwist map predictions with field line behaviour computed by a field line tracing computer program and observed experimentally.

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8

Chatenet, J. H., J. F. Luciani, and X. Garbet. "Self‐sustained magnetic islands." Physics of Plasmas 3, no. 12 (December 1996): 4628–36. http://dx.doi.org/10.1063/1.871586.

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9

Horiuchi, Ritoku. "The Role of Magnetic Islands in Collisionless Driven Reconnection: A Kinetic Approach to Multi-Scale Phenomena." Plasma 1, no. 1 (April 21, 2018): 68–77. http://dx.doi.org/10.3390/plasma1010007.

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The role of magnetic islands in collisionless driven reconnection has been investigated from the standpoint of a kinetic approach to multi-scale phenomena by means of two-dimensional particle-in-cell (PIC) simulation. There are two different types of the solutions in the evolution of the reconnection system. One is a steady solution in which the system relaxes into a steady state, and no island is generated (the no-island case). The other is an intermittent solution in which the system does not reach a steady state, and magnetic islands are frequently generated in the current sheet (the multi-island case). It is found that the electromagnetic energy is more effectively transferred to the particle energy in the multi-island case compared with the no-island case. The transferred energy is stored inside the magnetic island in the form of the thermal energy through compressional heating, and is carried away together with the magnetic island from the reconnection region. These results suggest that the formation of a magnetic island chain may have a potential to bridge the energy gap between macroscopic and microscopic physics by widening the dissipation region and strengthening the energy dissipation rate.

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10

Maret, Mireille, Fabiola Liscio, Denys Makarov, Jean-Paul Simon, Yves Gauthier, and Manfred Albrecht. "Morphology of epitaxial magnetic alloy nanostructures grown on WSe2(0001) studied by grazing-incidence small-angle X-ray scattering." Journal of Applied Crystallography 44, no. 6 (October 29, 2011): 1173–81. http://dx.doi.org/10.1107/s002188981104115x.

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The morphology of epitaxial alloy nanostructures grown on a van der Waals-type WSe2(0001) surface was studied using grazing-incidence small-angle X-ray scattering (GISAXS). Assemblies of 111-oriented islands of (Co,Cr)Pt3and (Co,Fe)Pt alloys were grown at different deposition temperatures, with nominal thicknesses from 0.1 to 3 nm, resulting in various island densities. Evaluation of the GISAXS patterns indicates that for similar growth conditions CrPt3islands are flatter than CoPt or FePt islands and exhibit larger island volumes. These features are correlated with the better wetting behaviour and more negative formation enthalpy of the CrPt3alloy. For dense arrays of self-assembled CoPt islands, much smaller island volumes are extracted from GISAXS experiments than are observed by scanning tunnelling microscope imaging, which indicates that only the upper parts of the islands contribute to the GISAXS signal. Another aspect that needs to be taken into account for interpreting GISAXS patterns is the sensitivity of GISAXS to facetting and thus its capacity to extract the island shape. The latter is strongly dependent on the island size. For islands with an average volume smaller than ∼20 nm3, the shape cannot be determined unequivocally. Furthermore, for dense island assemblies with some size dispersity, the identification of steep side-wall facets from the GISAXS patterns is not straightforward as observed for truncated tetrahedron-shaped CoPt3islands.

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11

Minardi, E. "Self-excitation of magnetic islands." Nuclear Fusion 34, no. 12 (December 1994): 1567–78. http://dx.doi.org/10.1088/0029-5515/34/12/i03.

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12

Tajima, T., and J. I. Sakai. "Explosive Coalescence of Magnetic Islands." IEEE Transactions on Plasma Science 14, no. 6 (1986): 929–33. http://dx.doi.org/10.1109/tps.1986.4316643.

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13

Marliani, C., and H. R. Strauss. "Reconnection of coalescing magnetic islands." Physics of Plasmas 6, no. 2 (February 1999): 495–502. http://dx.doi.org/10.1063/1.873193.

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14

Pucella, G., E. Alessi, F. Auriemma, P. Buratti, M. V. Falessi, E. Giovannozzi, F. Zonca, et al. "Beta-induced Alfvén eigenmodes and geodesic acoustic modes in the presence of strong tearing activity during the current ramp-down on JET." Plasma Physics and Controlled Fusion 64, no. 4 (March 10, 2022): 045023. http://dx.doi.org/10.1088/1361-6587/ac4ade.

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Abstract The analysis of the current ramp-down phase of JET plasmas has revealed the occurrence of additional magnetic oscillations in pulses characterized by large magnetic islands. The frequencies of these oscillations range from 5 to 20 kHz , being well below the toroidal gap in the Alfvén continuum and of the same order as the low-frequency gap opened by plasma compressibility. The additional oscillations only appear when the magnetic island width exceeds a critical threshold, suggesting that the oscillations could tap their energy from the tearing mode (TM) by a non-linear coupling mechanism. A possible role of fast ions in the excitation process can be excluded, being the pulse phase considered in the observations characterized by very low additional heating. The calculation of the coupled Alfvén–acoustic continuum in toroidal geometry suggests the possibility of beta-induced Alfvén eigenmodes (BAEs) rather than beta-induced Alfvén–acoustic eigenmodes. As a main novelty compared to previous work, the analysis of the electron temperature profiles from electron cyclotron emission has shown the simultaneous presence of magnetic islands on different rational surfaces in pulses with multiple magnetic oscillations in the low-frequency gap of the Alfvén continuum. This observation supports the hypothesis of different BAE with toroidal mode number n = 1 associated with different magnetic islands. As another novelty, the observation of magnetic oscillations with n = 2 in the BAE range is reported for the first time in this work. Some pulses, characterized by slowly rotating magnetic islands, exhibit additional oscillations with n = 0, likely associated with geodesic acoustic modes (GAMs), and a cross-spectral bicoherence analysis has confirmed a non-linear interaction between TM, BAE and GAM, with the novelty of the observation of multiple triplets (twin BAEs plus GAM), due to the simultaneous presence of several magnetic islands in the plasma.

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Fitzpatrick, Richard, and François L. Waelbroeck. "Two-fluid magnetic island dynamics in slab geometry. I. Isolated islands." Physics of Plasmas 12, no. 2 (February 2005): 022307. http://dx.doi.org/10.1063/1.1833375.

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16

Ivanov, N. V., and A. M. Kakurin. "LOCKING OF SMALL MAGNETIC ISLANDS BY ERROR FIELD IN T-10 TOKAMAK." Problems of Atomic Science and Technology, Ser. Thermonuclear Fusion 35, no. 1 (2012): 64–71. http://dx.doi.org/10.21517/0202-3822-2012-35-1-64-71.

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17

Könies, Axel, Jinjia Cao, Ralf Kleiber, and Joachim Geiger. "A numerical approach to the calculation of the Alfvén continuum in the presence of magnetic islands." Physics of Plasmas 29, no. 9 (September 2022): 092102. http://dx.doi.org/10.1063/5.0102239.

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A numerical approach is devised to calculate the shear Alfvén continuum inside and outside magnetic islands in cylindrical and stellarator plasmas. Equations for an appropriate set of coordinates and the arising equations for the continuum are derived and implemented in the CONTI code. An experiment-oriented representation of the results is chosen to allow a radial localization of the modes and a comparison of different magnetic configurations. Comparison is made with results of earlier analytic work for validation. Agreement is good but more details of the spectrum, such as the generation of island induced gaps inside and outside the separatrix, are found. While the code is easily usable and can be applied to any magnetic equilibrium accessible with VMEC, the calculations are plagued with convergence issues close to the separatrix. A calculation for a realistic W7-X equilibrium with islands is done where the island width is estimated with the HINT code.

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18

Ishizawa, A., and N. Nakajima. "Turbulence driven magnetic reconnection causing long-wavelength magnetic islands." Physics of Plasmas 17, no. 7 (July 2010): 072308. http://dx.doi.org/10.1063/1.3463435.

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Waelbroeck, F. L. "Theory and observations of magnetic islands." Nuclear Fusion 49, no. 10 (September 10, 2009): 104025. http://dx.doi.org/10.1088/0029-5515/49/10/104025.

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20

Smolyakov, A. I., H. R. Wilson, M. Ottaviani, and F. Porcelli. "Ion sound effects on magnetic islands." Plasma Physics and Controlled Fusion 46, no. 3 (February 12, 2004): L1—L6. http://dx.doi.org/10.1088/0741-3335/46/3/l01.

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21

Waelbroeck, F. L., and R. Fitzpatrick. "Rotation and Locking of Magnetic Islands." Physical Review Letters 78, no. 9 (March 3, 1997): 1703–6. http://dx.doi.org/10.1103/physrevlett.78.1703.

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22

Mikhalovskii, A. B., S. V. Konovalov, V. D. Pustovitov, V. S. Tsypin, R. M. O. Galvão, and I. C. Nascimento. "Electron drift effects on magnetic islands." Physics of Plasmas 8, no. 9 (September 2001): 4020–29. http://dx.doi.org/10.1063/1.1386938.

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23

White, R. B., and F. Romanelli. "Nonlinear self‐sustainment of magnetic islands." Physics of Fluids B: Plasma Physics 1, no. 5 (May 1989): 977–79. http://dx.doi.org/10.1063/1.858985.

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24

Chudnovskiy, A. N. "Model magnetic field configurations with islands." Plasma Physics Reports 30, no. 11 (November 2004): 907–17. http://dx.doi.org/10.1134/1.1825127.

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25

Nührenberg, Carolin, and Allen H. Boozer. "Magnetic islands and perturbed plasma equilibria." Physics of Plasmas 10, no. 7 (July 2003): 2840–51. http://dx.doi.org/10.1063/1.1578489.

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26

Miller, G., V. Faber, and A. B. White. "Finding plasma equilibria with magnetic islands." Journal of Computational Physics 79, no. 2 (December 1988): 417–35. http://dx.doi.org/10.1016/0021-9991(88)90023-x.

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27

Wang, Yulei, Xin Cheng, Mingde Ding, and Quanming Lu. "Annihilation of Magnetic Islands at the Top of Solar Flare Loops." Astrophysical Journal 923, no. 2 (December 1, 2021): 227. http://dx.doi.org/10.3847/1538-4357/ac3142.

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Abstract The dynamics of magnetic reconnection in the solar current sheet (CS) is studied by high-resolution 2.5-dimensional MHD simulation. With the commencing of magnetic reconnection, a number of magnetic islands are formed intermittently and move quickly upward and downward along the CS. Upon collision with the semi-closed flux of the flare loops, the downflow islands cause a second reconnection with a rate comparable with that in the main CS. Though the time-integrated magnetic energy release is still dominated by the reconnection in the main CS, the second reconnection can release substantial magnetic energy, annihilating the main islands and generating secondary islands with various scales at the flare loop top. The distribution function of the flux of the secondary islands is found to follow a power law varying from f ψ ∼ ψ − 1 (small scale) to ψ −2 (large scale), which seems to be independent to background plasma β and thermal conduction (TC). However, the spatial scale and the strength of the termination shocks driven by the main reconnection outflows or islands decrease if β increases or if TC is included. We suggest that the annihilation of magnetic islands at the flare loop top, which is not included in the standard flare model, plays a nonnegligible role in releasing magnetic energy to heat flare plasma and accelerate particles.

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Bhukta, Anjan, Dror Horvitz, Amit Kohn, and Ilan Goldfarb. "Lattice-Match Stabilization and Magnetic Properties of Metastable Epitaxial Permalloy-Disilicide Nanostructures on a Vicinal Si(111) Substrate." Nanomaterials 11, no. 5 (May 16, 2021): 1310. http://dx.doi.org/10.3390/nano11051310.

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We report the epitaxial formation of metastable γ-(FexNi1−x)Si2 nanostructure arrays resulting from the reaction of Ni80Fe20 permalloy with vicinal Si(111) surface atoms. We then explore the effect of structure and composition on the nanostructure’s magnetic properties. The low-temperature annealing (T < 600 °C) of a pre-deposited permalloy film led to solid-phase epitaxial nucleation of compact disk-shaped island nanostructures decorating <110> ledges of the stepped surface, with either (2 × 2) or (3×3) R30° reconstructed flat top faces. High resolution scanning transmission electron microscopy analysis demonstrated fully coherent epitaxy of the islands with respect to the substrate, consistent with a well-matched CaF2-prototype structure associated with γ-FeSi2, along perfect atomically sharp interfaces. Energy dispersive spectroscopy detected ternary composition of the islands, with Fe and Ni atoms confined to the islands, and no trace of segregation. Our magnetometry measurements revealed the superparamagnetic behavior of the silicide islands, with a blocking temperature around 30 K, reflecting the size, shape, and dilute arrangement of the islands in the assembly.

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29

Lu, S. S., Z. W. Ma, W. Tang, W. Zhang, and Y. Liu. "Numerical study on nonlinear double tearing mode in ITER." Nuclear Fusion 61, no. 12 (November 22, 2021): 126065. http://dx.doi.org/10.1088/1741-4326/ac3022.

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Abstract The nonlinear dynamics of the m/n = 2/1 double tearing mode (DTM) in ITER are systematically studied using the three-dimensional toroidal magnetohydrodynamic code, CLT. We carefully investigate the effects of the radial locations and magnetic shear strengths of the inner and outer rational surfaces r 1, r 2, s 1 and s 2, as well as the safety factor at the magnetic axis q 0 on DTM. It is found that the explosive burst takes place only with the moderate separation of the two rational surfaces or the stronger magnetic shear strength in which the strong interaction of magnetic islands in the two rational surfaces happens in the early nonlinear phase of the island development. The explosive burst can result from either the direct mutual driving associated with the fast growth island in the two rational surfaces or a strong nonlinear mode–mode coupling. For a large separation and a weak shear strength of the two rational surfaces, the magnetic islands saturate without strong interaction with each other, and (w in + w out)/2 is always below the separation Δr s. For a small separation, the kinetic evolution of DTM only exhibits an oscillation with a very low level and then decreases.

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Li, Yan, Lei Ni, Jing Ye, Zhixing Mei, and Jun Lin. "Particle Accelerations in a 2.5-dimensional Reconnecting Current Sheet in Turbulence." Astrophysical Journal 938, no. 1 (October 1, 2022): 24. http://dx.doi.org/10.3847/1538-4357/ac8b6d.

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Abstract Electric field induced in magnetic reconnection is an efficient mechanism for generating energetic particles, but the detailed role it plays is still an open question in solar flares. In this work, accelerations of particles in an evolving reconnecting current sheet are investigated via the test-particle approach, and the electromagnetic field is taken in a self-consistent fashion from a 2.5D numerical experiment for the magnetic reconnection process in the corona. The plasma instabilities like the tearing mode in the current sheet produce magnetic islands in the sheet, and island merging occurs as well. For the motion of the magnetic island, it yields the occurrence of the opposite electric field at both endpoints of the island; hence, tracking the accelerated particles around magnetic islands suggests that the parallel acceleration does not apparently impact the energy gain of particles, but the perpendicular acceleration does. Furthermore, our results indicate that the impact of the guide field on the trajectory of accelerated particles in a more realistic electromagnetic configuration works only on those particles that are energetic enough. The energy spectra of both species show a single power-law shape. The higher-energy component of the power-law spectrum results from the particles that are trapped in the current sheet, while the escaped and partly trapped particles contribute to the lower-energy component of the spectrum. The evolution of the spectrum shows a soft-hard-soft pattern that has been observed in flares.

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New, R. M. H. "Physical and magnetic properties of submicron lithographically patterned magnetic islands." Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 13, no. 3 (May 1995): 1089. http://dx.doi.org/10.1116/1.587908.

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32

Khaydukov, Yu N., Nikolai S. Perov, M. M. Borisov, E. Kh Mukhamedzhanov, A. Csik, K. N. Zhernenkov, Yu V. Nikitenko, and V. L. Aksenov. "Structural and Magnetic Properties of the Periodic [Fe(5nm)/V(5nm)]₁₀ and [Fe (3nm)/V(3nm)]₂₀ Systems." Solid State Phenomena 190 (June 2012): 396–400. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.396.

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Results of the study of the structural and magnetic properties of periodic Fe/V heterostructures with periods D = 9.4nm and D = 6.3nm are present. The study has shown that ferromagnetic islands are formed on the interfaces of Fe and V. These islands have different magnetic properties as sub-layers of pure iron. Islands in the sample with the period D = 9.4 nm have anisotropic shape, which leads to the anisotropy of magnetic properties.

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33

Mirnov, S. V. "Magnetic Islands and Current Filamentation in Tokamaks." Plasma Physics Reports 45, no. 2 (February 2019): 87–107. http://dx.doi.org/10.1134/s1063780x19020132.

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34

Hegna, C. C., and J. D. Callen. "Interaction of bootstrap‐current‐driven magnetic islands." Physics of Fluids B: Plasma Physics 4, no. 7 (March 1992): 1855–66. http://dx.doi.org/10.1063/1.860039.

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35

Smolyakov, A. I., and A. Hirose. "Small‐scale magnetic islands in collisionless plasmas." Physics of Fluids B: Plasma Physics 5, no. 3 (March 1993): 663–65. http://dx.doi.org/10.1063/1.860510.

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36

Persson, M. "Suppression of magnetic islands by plasma rotation." Nuclear Fusion 31, no. 2 (February 1, 1991): 382–86. http://dx.doi.org/10.1088/0029-5515/31/2/015.

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37

Porcelli, F., A. Airoldi, C. Angioni, A. Bruschi, P. Buratti, F. Califano, S. Cirant, et al. "Modelling of macroscopic magnetic islands in tokamaks." Nuclear Fusion 41, no. 9 (September 2001): 1207–18. http://dx.doi.org/10.1088/0029-5515/41/9/309.

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38

Waelbroeck, F. L., R. Fitzpatrick, and Daniela Grasso. "Effect of sheared flow on magnetic islands." Physics of Plasmas 14, no. 2 (February 2007): 022302. http://dx.doi.org/10.1063/1.2434251.

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39

Chen, L. J., A. Bhattacharjee, P. A. Puhl-Quinn, H. Yang, N. Bessho, S. Imada, S. Mühlbachler, et al. "Observation of energetic electrons within magnetic islands." Nature Physics 4, no. 1 (November 11, 2007): 19–23. http://dx.doi.org/10.1038/nphys777.

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40

Hayashi, T., T. Sato, H. J. Gardner, and J. D. Meiss. "Evolution of magnetic islands in a Heliac." Physics of Plasmas 2, no. 3 (March 1995): 752–59. http://dx.doi.org/10.1063/1.871427.

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41

Schumacher, J., and B. Kliem. "Coalescence of magnetic islands including anomalous resistivity." Physics of Plasmas 4, no. 10 (October 1997): 3533–43. http://dx.doi.org/10.1063/1.872250.

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42

Waelbroeck, F. L., F. Militello, R. Fitzpatrick, and W. Horton. "Effect of electrostatic turbulence on magnetic islands." Plasma Physics and Controlled Fusion 51, no. 1 (December 11, 2008): 015015. http://dx.doi.org/10.1088/0741-3335/51/1/015015.

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43

Siccinio, M., E. Poli, W. A. Hornsby, and A. G. Peeters. "Gyrokinetic investigation of magnetic islands in tokamaks." Journal of Physics: Conference Series 260 (November 1, 2010): 012019. http://dx.doi.org/10.1088/1742-6596/260/1/012019.

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Porcelli, F., E. Rossi, G. Cima, and A. Wootton. "Macroscopic Magnetic Islands and Plasma Energy Transport." Physical Review Letters 82, no. 7 (February 15, 1999): 1458–61. http://dx.doi.org/10.1103/physrevlett.82.1458.

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Persson, M., and A. Bondeson. "Oscillating magnetic islands in a rotating plasma." Physics of Fluids B: Plasma Physics 2, no. 10 (October 1990): 2315–21. http://dx.doi.org/10.1063/1.859496.

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Hu, Z. Q., Z. X. Wang, L. Wei, J. Q. Li, Y. Kishimoto, X. D. Lin, and X. Gao. "Structure bifurcation induced by wide magnetic islands." Nuclear Fusion 60, no. 5 (April 17, 2020): 056015. http://dx.doi.org/10.1088/1741-4326/ab7d1a.

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Agullo, O., M. Muraglia, A. Poyé, S. Benkadda, M. Yagi, X. Garbet, and A. Sen. "A signature for turbulence driven magnetic islands." Physics of Plasmas 21, no. 9 (September 2014): 092303. http://dx.doi.org/10.1063/1.4894699.

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Fitzpatrick, R., and F. L. Waelbroeck. "Drift-tearing magnetic islands in tokamak plasmas." Physics of Plasmas 15, no. 1 (January 2008): 012502. http://dx.doi.org/10.1063/1.2829757.

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Kos'ko, M., and E. Korago. "Review of geology of the New Siberian Islands between the Laptev and the East Siberian Seas, North East Russia." Stephan Mueller Special Publication Series 4 (September 17, 2009): 45–64. http://dx.doi.org/10.5194/smsps-4-45-2009.

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Abstract. The New Siberian Islands comprise De Long Islands, Anjou Islands, and Lyakhov Islands. Early Paleozoic, Mesozoic and Cenozoic sediments and igneous rocks are known on the De Long Islands. Cambrian slate, siltstone, mudstone and silicified limestone occur on Bennett Island. Ordovician volcanogenic turbidites, lavas, and small intrusions of andesite-basalt, basalt, dolerite, and porphyritic diorite were mapped on Henrietta Island. The igneous rocks are of calc-alkaline island arc series. The Ordovician age of the sequence was defined radiometrically. Early Paleozoic strata were faulted and folded presumably in the Caledonian time. Early Cretaceous sandstone and mudstone are known on Bennett Island. They are overlain by a 106–124 Ma basalt unit. Cenozoic volcanics are widespread on the De Long Islands. Zhokhov Island is an eroded stratovolcano. The volcanics are mostly of picrite-olivine type and limburgite. Radiometric dating indicates Miocene to Recent ages for Cenozoic volcanism. On the Anjou islands Lower-Middle Paleozoic strata consist of carbonates, siliciclastics, and clay. A Northwest-southeast syn-sedimentary facies zonation has been reconstructed. Upper Paleozoic strata are marine carbonate, clay and siliciclastic facies. Mudstone and clay predominate in the Triassic to Upper Jurassic section. Aptian-Albian coal bearing deposits uconformably overlap lower strata indicating Early Cretaceous tectonism. Upper Cretaceous units are mostly clay and siltstone with brown coal strata resting on Early Cretaceous weathered rhyolite. Cenozoic marine and nonmarine silisiclastics and clay rest upon the older units with a transgressive unconformity including a weathering profile in the older rocks. Manifestations of Paleozoic and Triassic mafic and Cretaceous acidic magmatism are also found on these islands. The pre-Cretaceous structure of the Anjou islands is of a block and fold type Late Cimmerian in age followed by faulting in Cenozoic time. The Lyakhov islands are located at the western end of the Late Cimmerian South Anyui suture. Sequences of variable age, composition, and structural styles are known on the Lyakhov Islands. These include an ancient metamorphic sequence, Late Paleozoic ophiolitic sequence, Late Mesozoic turbidite sequence, Cretaceous granites, and Cenozoic sediments. Fold and thrust imbricate structures have been mapped on southern Bol'shoi Lyakhov Island. North-northwestern vergent thrusts transect the Island and project offshore. Open folds of Jurassic–Early Cretaceous strata are characteristic of Stolbovoi and Malyi Lyakhov islands. Geology of the New Siberian Islands supports the concept of a circum Arctic Phanerozoic fold belt. The belt is comprised of Caledonian, Ellesmerian, Early Cimmerian and Late Cimmerian fold systems, manifested in many places on the mainland and on islands around the Arctic Ocean. Knowledge of the geology of the New Siberian Islands has been used to interpret anomalous gravity and magnetic field maps and Multi Channel Seismic (MCS) lines. Two distinguishing structural stages are universally recognized within the offshore sedimentary cover which correlate with the onshore geology of the New Siberian Islands. Dating of the upper structural stage and constituent seismic units is based on structural and stratigraphic relationships between Late Mesozoic and Cenozoic units in the archipelago. The Laptev Sea–western East Siberian Sea seismostratigraphic model for the upper structural stage has much in common with the seismostratigraphic model in the American Chukchi Sea.

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Ghasemloo, M., M. Ghoranneviss, and M. K. Salem. "The effect of biased limiter on the magnetic island width in tokamak plasma." Journal of Plasma Physics 80, no. 1 (December 13, 2013): 113–30. http://dx.doi.org/10.1017/s0022377813001190.

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AbstractIn this work the effects of Cold Biased Limiter (CBL) and Emissive Biased Limiter (EBL) have been individually investigated, in both positive and negative polarities, on the width and frequency of magnetic islands. The effects were examined using singular value decomposition and wavelet techniques on mirnov coil signals. The results show that the application of EBL with both positive and negative polarities has been more effective on plasma stability compared with CBL. Comparing different polarities of CBL and EBL revealed that the positive polarity was more effective on the width of magnetic islands than negative polarity. The greatest impact occurs during EBL with positive polarity, in which reduction is observed in both width of magnetic islands and emission of Hα radiation. Besides, intensity and frequency of magnetic islands are reduced from 50 to 25 kHz in around 1 ms after bias application. Meanwhile, the minimal effect on width and frequency of magnetic field occurs in CBL with negative polarity.

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Journal articles on the topic 'Magnetic Islands'

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