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Persistent 1.5 s oscillations superimposed to a solar burst observed at two mm-wavelengths

Zodi, A. M. and Kaufmann, P. and Zirin, H. (1984) Persistent 1.5 s oscillations superimposed to a solar burst observed at two mm-wavelengths. Solar Physics, 92 (1-2). pp. 283-298. ISSN 0038-0938. doi:10.1007/bf00157252.

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Long-enduring quasi-periodic oscilations (1.5s) superimposed upon a solar burst have for the first time been observed simultaneously at two different mm-wavelengths (22 GHz and 44 GHz). The oscillations were present throughout the burst duration (about 10 min), and were delayed at 44 GHz with respect to 22 GHz by 0.3 s. The relative amplitude of the oscillation was of about 20% at 44 GHz and of about 5% at 22 GHz. Interferometer measurements at 10.6 GHz indicated the burst source position stable within 1 arc sec. An He I D₃ line flare showed two persistent small spots separated by about 10 arc sec. The 22/44 GHz burst position corresponds well with the location of the He I D₃ spots. The oscillations display features which distinguish them from ultrafast time structures found in other bursts. One possible interpretation is a modulation of the synchrotron emission of trapped electrons by a variable magnetic field on a double burst source, optically thin at 44 GHz and with optical thickness ⪞ 0.3 at 22 GHz.

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Additional Information:© 1984 Kluwer Academic Publishers. Provided by the NASA Astrophysics Data System. Received 31 May, 1983; in revised form 2 February, 1984. We are grateful to the referee, whose corrections and suggestions have improved the clarity of this paper. We acknowledge Dr G. J. Hurford (CALTECH) in providing OVRO 10.6 GHz interferometer data on this event. We also are grateful for the useful discussions about this research made with H. S. Sawant, J.C. Brown, E. Correia, and J. E. R. Costa. This research was partially supported by Brazilian Research agencies FINEP and FAPESP. INPE operates CRAAM and Itapetinga Radio Observatory.
Funding AgencyGrant Number
Financiadora de Estudos e Projetos (FINEP)UNSPECIFIED
Fundação de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP)UNSPECIFIED
Subject Keywords:Flare; Optical Thickness; Trap Electron; Time Structure; Source Position
Issue or Number:1-2
Record Number:CaltechAUTHORS:20200602-150218430
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Official Citation:Zodi, A.M., Kaufmann, P. & Zirin, H. Persistent 1.5 s oscillations superimposed to a solar burst observed at two mm-wavelengths. Sol Phys 92, 283–298 (1984).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103647
Deposited By: Tony Diaz
Deposited On:02 Jun 2020 22:39
Last Modified:16 Nov 2021 18:23

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