Dynamics of magneto-hydrodynamical oscillations from observations of the solar active region NOAA 0119 over a range of wavelengths from 2.0 to 107 cm
Budzinovskaia, IA, Tsvetkov, LI, 1Yurovsky, YF 1Crimean Astrophysical Observatory, Nauchny, Ukraine |
Kinemat. fiz. nebesnyh tel (Online) 2004, 20(2):165-175 |
Language: Russian |
Abstract: Observations of variations of radio emission of active regions on 23 September 2002 at seven wavelengths from 2.0 cm up to 107 cm are carried out. It is found from the wavelet analysis that intensity fluctuations existed over the whole range of observed wavelengths. The Fourier spectrum of fluctuations over a range of frequencies 1—5 mHz (periods 200—1000 s) was not flat and was characterized by reduction of spectral index from p = -1.9 at wavelengths 2.0—3.5 cm up to p = -0.8 at metre range 100—107 cm. Wavelet spectra testify that during time interval from 9:00 to 10:53 UT the greatest oscillations have a period about 970 s. The oscillations with this period were correlated at all the waves from 2.0 cm up to 107 cm. The phase of oscillations at short wavelength had systematic shifts of opposite sign relative to long waves with a boundary wavelength at 10.5 cm. This property is considered as an occurrence of disturbance at height of generation of dm-radiation and its propagation in the solar atmosphere simultaneously to upwards and downwards directions. |
Keywords: solar activity |