Determination of Plasma Parameters in Radio Sources of Solar Zebra-patterns Based on Relations between the Zebra-stripe Frequencies and Gyro-harmonic Numbers

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Abstract
Solar radio zebras belong to the most important radio fine structures used in diagnostics of solar flare plasmas. In the present paper, assuming the double plasma-resonance model of zebras, we study the relation between zebra-stripe frequencies and gyro-harmonic numbers. We artificially generated two possible types of zebras: the zebra with Sequence A and Sequence B, where an increase of the zebra-stripe frequency corresponds to decrease or increase of the gyro-harmonic number. Analyzing these ideal zebras, we found that the frequency ratios of the neighboring zebra stripes increase in zebras with Sequence A and decrease in zebras with Sequence B. This criterion and corresponding diagrams were applied for nine observed zebras. All these zebras were found to be with Sequence A. Then we checked and confirmed these results by using the new numerical method, where the gyro-harmonic numbers of the zebra stripes with the lowest frequency s 1 were also determined. We found that in all these zebras, the spatial scale of the magnetic field in the zebra-stripe sources was always shorter than that of the plasma density. Knowing the gyro-harmonic numbers and corresponding zebra-stripe frequencies, we determined the magnetic field and plasma density in zebra sources to be 0.84–37.31 G and 0.026 × 1010–16.03 × 1010 cm−3, respectively. Finally, we found that with increasing the gyro-harmonic number s 1, the ratio of perpendicular and parallel scales of the magnetic field and plasma density in the zebra-stripe sources also increases.

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