Hercules A

Hercules A
Radio-Optical View of the Galaxy Hercules A - Many thanks to: NASA, ESA, S. Baum and C. O'Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA)

Friday, August 8, 2014

Definition: solar type Zebra - Spatially and Spectrally Resolved Observations

I refer to Chen Bastian Gary and Ju Jing 2011:


"Spatially and Spectrally Resolved Observations of a Zebra Pattern in a Solar Decimetric Radio Burst"

Abstract: "We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (≈1 MHz) and high time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope Subsystem Testbed (FST) and the Owens Valley Solar Array (OVSA) were used in parallel to observe the X1.5 flare on 2006 December 14. By using OVSA to calibrate the FST, the source position of the zebra pattern can be located on the solar disk. With the help of multi-wavelength observations and a nonlinear force-free field extrapolation, the zebra source is explored in relation to the magnetic field configuration. New constraints are placed on the source size and position as a function of frequency and time. We conclude that the zebra burst is consistent with a double-plasma resonance model in which the radio emission occurs in resonance layers where the upper-hybrid frequency is harmonically related to the electron cyclotron frequency in a coronal magnetic loop."

"...ZP [zebra patterns] bursts appear in radio dynamic spectra as closely-spaced, quasi-parallel bands of emission, typically ranging from ~ 5−20 in number
but sometimes showing as many as 70...They have been observed at meter wavelengths for decades..."