Zebra Stripes with High Gyro-Harmonic Numbers
| dc.contributor.author | Benáček, Jan | |
| dc.contributor.author | Karlický , Marian | |
| dc.date.accessioned | 2023-01-25T14:20:14Z | |
| dc.date.available | 2023-01-25T14:20:14Z | |
| dc.date.issued | 2022-08-18 | |
| dc.description.abstract | Solar radio zebras are used in the determination of the plasma density and magnetic field in solar flare plasmas. Analyzing observed zebra stripes and assuming their generation by the double-plasma resonance (DPR) instability, high values of the gyro-harmonic number are found. In some cases they exceed one hundred, in disagreement with the DPR growth rates computed up to now, which decrease with increasing gyro-harmonic number. We address the question of how zebras with high values of the gyro-harmonic numbers s are generated. For this purpose, we compute the growth rates of the DPR instability in a very broad range of s, considering a loss-cone κ-distribution of superthermal electrons and varying the loss-cone angle, electron energies, and background plasma temperature. We have numerically calculated the dispersion relations and the growth rates of the upper-hybrid waves and found that the growth rates increase with increasing gyro-harmonic numbers if the loss-cone angles are ∼80∘. The highest growth rates for these loss-cone angles are obtained for velocity vκ=0.15c. The growth rates as a function of the gyro-harmonic number still show well distinct peaks, which correspond to zebra-stripe frequencies. The contrast between peak growth rates and surrounding growth ratelevels increases as the κ index increases and the background temperature decreases. Zebras with high values of s can be generated in regions where loss cone distributions of superthermal electrons with large loss-cone angles (∼80∘) are present. Furthermore, owing to the high values of s, the magnetic field is relatively weak and has a small spatial gradient in such regions. | en |
| dc.description.sponsorship | TU Berlin, Open-Access-Mittel – 2022 | |
| dc.identifier.eissn | 1573-093X | |
| dc.identifier.issn | 0038-0938 | |
| dc.identifier.uri | https://depositonce.tu-berlin.de/handle/11303/18072 | |
| dc.identifier.uri | https://doi.org/10.14279/depositonce-16864 | |
| dc.language.iso | en | |
| dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | |
| dc.subject.ddc | 530 Physik | de |
| dc.subject.other | radio bursts | en |
| dc.subject.other | radio emission | en |
| dc.subject.other | instabilities | en |
| dc.title | Zebra Stripes with High Gyro-Harmonic Numbers | en |
| dc.type | Article | |
| dc.type.version | publishedVersion | |
| dcterms.bibliographicCitation.articlenumber | 103 | |
| dcterms.bibliographicCitation.doi | 10.1007/s11207-022-02036-y | |
| dcterms.bibliographicCitation.journaltitle | Solar Physics | |
| dcterms.bibliographicCitation.originalpublishername | Springer Nature | |
| dcterms.bibliographicCitation.originalpublisherplace | Heidelberg | |
| dcterms.bibliographicCitation.volume | 297 | |
| dcterms.rightsHolder.reference | Creative-Commons-Lizenz | |
| tub.accessrights.dnb | free | |
| tub.affiliation | Fak. 2 Mathematik und Naturwissenschaften::Zentrum für Astronomie und Astrophysik::N/A (Not Applicable) | |
| tub.publisher.universityorinstitution | Technische Universität Berlin |