Outbursts from a Black Hole via Alfven Wave to Electromagnetic Wave Mode Conversion

1998 ◽  
Vol 498 (1) ◽  
pp. 296-306 ◽  
Author(s):  
James Daniel ◽  
Toshiki Tajima
Keyword(s):  
Black Hole ◽  
Electromagnetic Wave ◽  
Mode Conversion ◽  
Wave Mode ◽  
Alfven Wave

scholarly journals Collisionless Damping of Fast and Ion?Cyclotron Surface Waves

1993 ◽  
Vol 46 (2) ◽  
pp. 271 ◽  
Author(s):  
GW Rowe
Keyword(s):  
Surface Waves ◽  
Short Wavelength ◽  
Mode Conversion ◽  
Low Frequency ◽  
Wave Mode ◽  
Alfven Wave ◽  
Field Boundary ◽  
First Order ◽  
Vacuum Interface ◽  
Ion Cyclotron

A recently developed general kinetic theory of surface waves is used to calculate the collisionless damping of low frequency fast and ion-cyclotron surface waves on a magnetised plasma-vacuum interface. In particular, the possibility of Cherenkov (Landau and transit-time magnetic) absorption by electrons is accounted for, assuming a bi-Maxwellian distribution of electrons in velocity space. It is shown that in general the surface waves are damped via mode conversion to a short-wavelength mode, such as the kinetic Alfven wave, which is subsequently Landau absorbed within the plasma. For high temperatures this short-wavelength mode can also be radiated into the plasma without being completely absorbed. It is also shown that the related ion-sound surface wave mode and instability identified by Alexandrov et al. (1984) are unphysical, and are the result of neglecting the gas pressure in the first-order magnetic field boundary condition.

scholarly journals Alfvén Wave Mode Conversion in Pulsar Magnetospheres

2021 ◽  
Vol 908 (2) ◽  
pp. 176
Author(s):  
Yajie Yuan ◽  
Yuri Levin ◽  
Ashley Bransgrove ◽  
Alexander Philippov
Keyword(s):  
Mode Conversion ◽  
Wave Mode ◽  
Alfven Wave

Scattering of ordinary electromagnetic wave on the kinetic alfven wave

1999 ◽  
Vol 5 (1) ◽  
pp. 48-51
Author(s):  
A.K. Yukhimuk ◽  
◽  
V.A. Yukhimuk ◽  
O.G. Fal'ko ◽  
E.K. Sirenko ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Alfven Wave ◽  
Kinetic Alfvén Wave ◽  
Kinetic Alfven Wave

Fast wave mode conversion in three-ion component plasmas

2008 ◽  
Author(s):  
Yevgen Kazakov ◽  
Ivan Pavlenko ◽  
Igor Girka ◽  
Boris Weyssow
Keyword(s):  
Mode Conversion ◽  
Wave Mode ◽  
Fast Wave

Investigation of transcranial ultrasound delivery via Lamb wave mode conversion leveraging a transducer pair

2021 ◽  
Vol 150 (4) ◽  
pp. A32-A32
Author(s):  
Matteo Mazzotti ◽  
Eetu Kohtanen ◽  
Alper Erturk ◽  
Massimo Ruzzene
Keyword(s):  
Lamb Wave ◽  
Mode Conversion ◽  
Wave Mode ◽  
Transcranial Ultrasound

scholarly journals Wave particle interactions in the high-altitude polar cusp: a Cluster case study

2005 ◽  
Vol 23 (12) ◽  
pp. 3699-3713 ◽  
Author(s):  
B. Grison ◽  
F. Sahraoui ◽  
B. Lavraud ◽  
T. Chust ◽  
N. Cornilleau-Wehrlin ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
High Altitude ◽  
Wave Spectrum ◽  
Alfven Waves ◽  
Wave Activity ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Plasma Convection ◽  
Field Lines ◽  
Kinetic Alfvén Waves

Abstract. On 23 March 2002, the four Cluster spacecraft crossed in close configuration (~100 km separation) the high-altitude (10 RE) cusp region. During a large part of the crossing, the STAFF and EFW instruments have detected strong electromagnetic wave activity at low frequencies, especially when intense field-aligned proton fluxes were detected by the CIS/HIA instrument. In all likelihood, such fluxes correspond to newly-reconnected field lines. A focus on one of these ion injection periods highlights the interaction between waves and protons. The wave activity has been investigated using the k-filtering technique. Experimental dispersion relations have been built in the plasma frame for the two most energetic wave modes. Results show that kinetic Alfvén waves dominate the electromagnetic wave spectrum up to 1 Hz (in the spacecraft frame). Above 0.8 Hz, intense Bernstein waves are also observed. The close simultaneity observed between the wave and particle events is discussed as an evidence for local wave generation. A mechanism based on current instabilities is consistent with the observations of the kinetic Alfvén waves. A weak ion heating along the recently-opened field lines is also suggested from the examination of the ion distribution functions. During an injection event, a large plasma convection motion, indicative of a reconnection site location, is shown to be consistent with the velocity perturbation induced by the large-scale Alfvén wave simultaneously detected.

scholarly journals Poroelastic property analysis of seismic low-frequency shadows associated with gas reservoirs

2020 ◽  
Vol 17 (3) ◽  
pp. 463-474
Author(s):  
Shengjie Li ◽  
Ying Rao
Keyword(s):  
Mode Conversion ◽  
Low Frequency ◽  
Simulation Method ◽  
Wave Mode ◽  
Pore Fluid ◽  
Fluid Distribution ◽  
Gas Reservoirs ◽  
Tight Sandstone ◽  
Reservoir Properties ◽  
Gas Bearing

Abstract Seismic low-frequency amplitude shadows have been widely used as a hydrocarbon indicator. This study investigates the effect of reservoir properties and seismic wave mode conversion on the characteristics of the low-frequency amplitude shadows in gas-bearing reservoirs. The target gas reservoirs are typically related to the lithology of tight sandstone with strong heterogeneity. Pore-fluid distribution within the reservoirs presents patchy saturation in the vertical and horizontal directions, and this patchy saturation easily induces low-frequency shadows beneath gas-bearing reservoirs. These low-frequency shadows are validated by using a poroelastic simulation method. The results of our field case-based study indicate that pore-fluid property, plus the thickness and heterogeneity of reservoirs are the key elements in the generation of low-frequency shadows. The results also indicate that the poroelastic simulation method can be used to effectively predict the spatial distribution of gas-bearing reservoirs, by directly verifying the low-frequency shadow phenomenon existing in the seismic data.

Whistler Wave Mode Conversion to Lower Hybrid Waves at a Density Striation

1994 ◽  
Vol 73 (22) ◽  
pp. 2990-2993 ◽  
Author(s):  
J. F. Bamber ◽  
W. Gekelman ◽  
J. E. Maggs
Keyword(s):  
Mode Conversion ◽  
Wave Mode ◽  
Whistler Wave ◽  
Lower Hybrid ◽  
Hybrid Waves ◽  
Lower Hybrid Waves
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