Abstract
The results of 2 1/2 years (July 1967 – December 1969) monitoring of solar radio bursts at 71 GHz (λ = 4.2 mm) at the Radio and Space Research Station, Slough are presented. During this period only seven events were positively identified as 71 GHz bursts. One of these events (6 July, 1968) is among the largest solar bursts ever recorded anywhere in the microwave-millimetre wave band (47000 × 10−22Wm−2Hz−1), and the associated magnetic field may possibly have exceeded 7200 G. Another event (27 March, 1969) has demonstrated that bursts at 71 GHz can be both intense (4700 × 10−22Wm−2Hz−1) and complex. On other occasions, the absence of any detectable event at 71 GHz helps to define the high frequency spectrum of the burst, this being an important factor in determining the initial energy distribution of the electrons ejected by the associated flare. On one such occasion (21 March, 1969) the derived energy distribution index γ is ⩾ 8, in contrast with the more usual values of 2–4.
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References
Coates, R. J.: 1958, ‘Measurements of Solar Radiation and Atmospheric Attenuation at 4.3 Millimetres Wavelength’, Proc. IRE 46, 122.
Coates, R. J.: 1966, ‘Solar Observations at Millimetre Wavelengths’, Proc. IEEE 54, 471.
Croom, D. L.: 1970, ‘19 GHz (1.58 cm) Solar Radio Bursts as Indicators of Proton Events’, to be published.
Croom, D. L. and Powell, R. J.: 1969, ‘Outstanding Solar Radio Burst at 4.2 mm’, Nature 221, 945.
Croom, D. L. and Powell, R. J.: 1970, ‘19 GHz (1.58 cm) Solar Radio Bursts in the Period July 1967 to December 1969’, submitted to J. Geophys. Res.
Croom, D. L., Powell, R. J., and Harris, L. D. J.: 1970, ‘Slough Solar Radio Observatory’, Solar Phys. 14, 238.
ESSA, Solar Geophysical Data, 1969, IER-FB-296, Environmental Science Services Administration, Boulder, Colo.
Feix, G.: 1970, ‘Solar Bursts at Millimetre Wavelengths’, J. Geophys. Res. 75, 211.
Takakura, T.: 1967, ‘Theory of Solar Bursts’, Solar Phys. 1, 304.
Takakura, T., Uchida, Y., and Kai, K.: 1968, ‘Time Variation of the Spectrum of Gyro-Synchrotron Emission from the Sun’, Solar Phys. 4, 45.
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1969–1970 NCR-OAR Senior Post-Doctoral Research Associate at Air Force Cambridge Research Laboratories, L. G. Hanscom Field, Bedford, Mass., U.S.A.
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Croom, D.L. 71 GHz (4.2 mm) solar radio bursts in the period July 1967 to December 1969. Sol Phys 15, 414–423 (1970). https://doi.org/10.1007/BF00151848
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DOI: https://doi.org/10.1007/BF00151848