scholarly journals Frequency-dependent polarization-angle-phase-shift in the microwave-induced magnetoresistance oscillations

2015 ◽  
Vol 117 (6) ◽  
pp. 064306 ◽  
Author(s):  
Han-Chun Liu ◽  
Tianyu Ye ◽  
W. Wegscheider ◽  
R. G. Mani
Keyword(s):  
Phase Shift ◽  
Polarization Angle ◽  
Frequency Dependent ◽  
Dependent Polarization ◽  
Magnetoresistance Oscillations

scholarly journals Angular phase shift in polarization-angle dependence of microwave-induced magnetoresistance oscillations

2016 ◽  
Vol 94 (24) ◽  
Author(s):  
Han-Chun Liu ◽  
Rasanga L. Samaraweera ◽  
R. G. Mani ◽  
C. Reichl ◽  
W. Wegscheider
Keyword(s):  
Phase Shift ◽  
Polarization Angle ◽  
Angle Dependence ◽  
Magnetoresistance Oscillations

scholarly journals Constraints on Lorentz Invariance Violation with Multiwavelength Polarized Astrophysical Sources

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 44
Author(s):  
Qi-Qi Zhou ◽  
Shuang-Xi Yi ◽  
Jun-Jie Wei ◽  
Xue-Feng Wu
Keyword(s):  
Gamma Ray ◽  
Lorentz Invariance ◽  
Polarized Light ◽  
Polarization Plane ◽  
Polarization Angle ◽  
Intrinsic Polarization ◽  
Frequency Dependent ◽  
Invariance Violation ◽  
Linearly Polarized ◽  
Order Of Magnitude

Possible violations of Lorentz invariance (LIV) can produce vacuum birefringence, which results in a frequency-dependent rotation of the polarization plane of linearly polarized light from distant sources. In this paper, we try to search for a frequency-dependent change of the linear polarization angle arising from vacuum birefringence in the spectropolarimetric data of astrophysical sources. We collect five blazars with multiwavelength polarization measurements in different optical bands (UBVRI). Taking into account the observed polarization angle contributions from both the intrinsic polarization angle and the rotation angle induced by LIV, and assuming that the intrinsic polarization angle is an unknown constant, we obtain new constraints on LIV by directly fitting the multiwavelength polarimetric data of the five blazars. Here, we show that the birefringence parameter η quantifying the broken degree of Lorentz invariance is limited to be in the range of −9.63×10−8<η<6.55×10−6 at the 2σ confidence level, which is as good as or represents one order of magnitude improvement over the results previously obtained from ultraviolet/optical polarization observations. Much stronger limits can be obtained by future multiwavelength observations in the gamma-ray energy band.

scholarly journals A fast radio burst with frequency-dependent polarization detected during Breakthrough Listen observations

2019 ◽  
Vol 486 (3) ◽  
pp. 3636-3646 ◽  
Author(s):  
D C Price ◽  
G Foster ◽  
M Geyer ◽  
W van Straten ◽  
V Gajjar ◽  
...  
Keyword(s):  
Radio Burst ◽  
Dynamic Spectrum ◽  
Radio Interference ◽  
Fractional Bandwidth ◽  
Frequency Dependent ◽  
Polarization Voltage ◽  
Geosynchronous Satellite ◽  
Object Based ◽  
Dependent Polarization ◽  
Fast Radio Burst

ABSTRACT Here, we report on the detection and verification of fast radio burst FRB 180301, which occurred on utc 2018 March 1 during the Breakthrough Listen observations with the Parkes telescope. Full-polarization voltage data of the detection were captured – a first for non-repeating FRBs – allowing for coherent de-dispersion and additional verification tests. The coherently de-dispersed dynamic spectrum of FRB 180301 shows complex, polarized frequency structure over a small fractional bandwidth. As FRB 180301 was detected close to the geosynchronous satellite band during a time of known 1–2 GHz satellite transmissions, we consider whether the burst was due to radio interference emitted or reflected from an orbiting object. Based on the pre-ponderance of our verification tests, we cannot conclusively determine FRB 180301 to be either astrophysical or anthropogenic in origin.

Martian Aquifers: Detection by Magnetic Sounding from Surface Magnetometry

2020 ◽  
Author(s):  
Yanan Yu ◽  
Janet Luhmann ◽  
Christopher Russell
Keyword(s):  
Frequency Dependence ◽  
Vertical Component ◽  
Frequency Dependent ◽  
Source Regions ◽  
Magnetic Pulsations ◽  
Dependent Polarization ◽  
Surface Observations

&lt;p&gt;Magnetic pulsations are observed at Mars in the magnetotail and on the surface by the Maven and InSight magnetometers. The surface observations exhibit a frequency-dependent polarization in which the amplitude of the vertical component weakens with increasing frequency. This frequency dependence is not seen in the source regions studied by MAVEN. The source of the frequency dependence must be in the subsurface of Mars. The attenuation is consistent with an aquifer that is 3 km thick, containing water of the conductivity of terrestrial seawater.&lt;/p&gt;

Frequency dependent refocusing in phase shift beamforming systems

1981 ◽  
Vol 70 (3) ◽  
pp. 749-755 ◽  
Author(s):  
James F. Lynch ◽  
Robert H. Stokes
Keyword(s):  
Phase Shift ◽  
Frequency Dependent

scholarly journals Seismic signature of turbulence during the 2017 Oroville Dam spillway erosion crisis

2018 ◽  
Author(s):  
Phillip J. Goodling ◽  
Vedran Lekic ◽  
Karen Prestegaard
Keyword(s):  
Turbulent Flow ◽  
Rayleigh Wave ◽  
Flood Control ◽  
Large Scale ◽  
Source Location ◽  
Scaling Exponent ◽  
Polarization Analysis ◽  
Frequency Dependent ◽  
Turbulent Eddies ◽  
Dependent Polarization

Abstract. Knowing the location of large-scale turbulent eddies during catastrophic flooding events improves predictions of erosive scour. The erosion damage to the Oroville Dam flood control spillway in early 2017 is an example of the erosive power of turbulent flow. During this event, a defect in the simple concrete channel quickly eroded into a chasm 47 meters deep. Erosion by turbulent flow is difficult to evaluate in real time, but near-channel seismic monitoring provides a tool to evaluate flow dynamics from a safe distance. Previous studies have had limited ability to identify source location or the type of surface wave (i.e. Love or Rayleigh wave) excited by different river processes. Here we use a single three-component seismometer method (Frequency-Dependent Polarization Analysis) to characterize the dominant seismic source location and seismic surface waves produced by the Oroville dam flood control spillway, using the abrupt change in spillway geometry as a natural experiment. We find that the scaling exponent between seismic power and release discharge is greater following damage to the spillway, suggesting larger turbulent eddies excite more seismic energy. The mean azimuth in the 5–10 Hz frequency band was used to resolve the location of spillway damage. Observed polarization attributes deviate from those expected for a Rayleigh wave, though numerical modelling indicates these deviations are explained by propagation up the hillside topography. Our results suggest Frequency-Dependent Polarization Analysis is a promising approach for locating areas of increased flow turbulence. This method could be applied to other erosion problems near engineered structures and to understanding energy dissipation, erosion, and channel morphology development in natural rivers, particularly at high discharges.

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