Coronal heating by quasi-2D MHD turbulence driven by non-WKB wave reflection

1999 ◽  
Author(s):  
William H. Matthaeus ◽  
Gary P. Zank ◽  
Sean Oughton
Keyword(s):  
Wave Reflection ◽  
Coronal Heating ◽  
Mhd Turbulence

scholarly journals Coronal Heating, Weak MHD Turbulence, and Scaling Laws

2007 ◽  
Vol 657 (1) ◽  
pp. L47-L51 ◽  
Author(s):  
A. F. Rappazzo ◽  
M. Velli ◽  
G. Einaudi ◽  
R. B. Dahlburg
Keyword(s):  
Scaling Laws ◽  
Coronal Heating ◽  
Mhd Turbulence

Coronal heating by selective decay of MHD turbulence

Solar Physics ◽  
1988 ◽  
Vol 116 (1) ◽  
Author(s):  
D. G�mez ◽  
C.Ferro Font�n
Keyword(s):  
Coronal Heating ◽  
Mhd Turbulence ◽  
Selective Decay

scholarly journals MAGNETOHYDRODYNAMIC WAVES AND CORONAL HEATING: UNIFYING EMPIRICAL AND MHD TURBULENCE MODELS

2013 ◽  
Vol 764 (1) ◽  
pp. 23 ◽  
Author(s):  
Igor V. Sokolov ◽  
Bart van der Holst ◽  
Rona Oran ◽  
Cooper Downs ◽  
Ilia I. Roussev ◽  
...  
Keyword(s):  
Turbulence Models ◽  
Coronal Heating ◽  
Mhd Turbulence ◽  
Magnetohydrodynamic Waves

scholarly journals Observations and Models of Coronal Heating

2001 ◽  
Vol 203 ◽  
pp. 456-466
Author(s):  
F. Malara ◽  
M. Velli
Keyword(s):  
Energy Release ◽  
Power Law ◽  
Magnetic Energy ◽  
Detection Threshold ◽  
Solar Radius ◽  
Coronal Heating ◽  
Fast Wave ◽  
Mhd Turbulence ◽  
Small Energy ◽  
Power Law Distributions

Energy release in the solar Corona is characterized by a sequence of space and time localized events, whose intensity follows power-law distributions. In quiet Sun regions, small energy events, possibly under the detection threshold, dominate, thus supporting the “nanoflare” scenario of coronal heating. Two complementar models of heating are discussed, in connection with the above observational features. The first model is based on Alfvénic wavepackets dissipation in 3D force-free magnetic fields; the presence of regions of chaoticity of magnetic lines allows for a fast wave dissipation, within a fraction of a solar radius. The second model describes a MHD turbulence in low-β plasma, in which magnetic energy is continuously furnished by slow photospheric motions. Energy release events corresponds dissipation of current sheets, often associated with magnetic reconnection. The resulting distribution of dissipated power follows a power law, similar to observations.

scholarly journals Coronal Heating by D.C. Currents

1990 ◽  
Vol 142 ◽  
pp. 207-214
Author(s):  
J. Heyvaerts
Keyword(s):  
Coronal Heating ◽  
Mhd Turbulence ◽  
Dc Current

Present views on DC current coronal heating are presented. The relation to AC mechanisms, the importance of MHD turbulence in both processes, and the convergence of presently proposed ideas is outlined.

On the Effect of 2-Layer Thickness by High-Specific Gravity Armor Blocks on Wave Reflection

1999 ◽  
Author(s):  
Masahiro Ito ◽  
Yuitch Iwagaki ◽  
Hiroshi Murakami ◽  
Kenji Nemoto ◽  
Masato Yamamoto ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Layer Thickness ◽  
Wave Reflection ◽  
High Specific Gravity

Detection of delamination in composites by using electromagnetic penetrating radar

2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Wave Reflection ◽  
Image Features ◽  
Partial Reflection ◽  
Straight Path ◽  
Reflected Signal ◽  
Short Time ◽  
Intervening Factors

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.

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