نوع مقاله : مقاله پژوهشی
نویسندگان
گروه فیزیک، دانشگاه پیام نور، تهران، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The mechanism of wave dissipation in different layers of the sun, as well as the solar granules inter-network bright points and internetwork bright points of chromosphoric solar granules, have been explored in this article. This article's data come from the Interface Region Imaging Spectrograph (IRIS). IRIS is a small exploration mission by NASA. That obtains spectra in near-ultraviolet (NUV), far-ultraviolet 1 (FUV1), and far-ultraviolet 2 (FUV2), from 1332 to 2834 . Slit jaw images (SJIs) of IRIS, using various filters that can provide images centered on the Mg II h wing, Mg II k, Si IV 1403 , and C ii lines. To begin, bright points in the chromosphere are selected for this goal. These points were first chosen using IRIS Slit Jaw Images (SJI) Si IV 1403 . The time slices of the Doppler velocity of the Mg II k spectrum are then drawn at a specified velocity (+/- 20 km/s) and were fed into the wavelet transform function to perform the time-frequency analysis to obtain the oscillation periods of the Doppler velocity. The wavelet transform used for this purpose is Morlet 5 wavelet.
The velocity oscillation period data are utilized to determine the bright points of the network and internetwork solar granules at the chromosphere. The Doppler shift diagram for the Si IV 1394 spectral line is then displayed in time. This graph is a Doppler shift various time graph with attenuation that is caused by wave loss in the solar layers. According to the obtained data, the network and internetwork bright points, the chromospheric solar granules have an attenuation time 3 to 5 min. The oscillations of the solar granules network bright points are damped more intensely than the solar granules inter-network bright points, and hence their damping lifetime is shorter. Si IV 1394 Doppler velocity shift of bright points placed in the solar granules inter-network is dampened by a lower slope and so has a longer damping life time.
Sadeghi and Tavabi researched about the kinetic energy above the bright points of the network and internetwork regions of the solar granules in a part of a paper titled "A new approach to kinetic energy flux at the different frequencies above the IRIS bright points" in 2022. They claim that a substantial percentage of the energy of the network bright points of solar granules is transferred to higher layers, namely the transition region corona, in the network bright points of solar granules. These findings are congruent with the findings of the current study. The oscillations in these locations are dampened for a brief period of time, and the energy is transmitted to higher layers with little loss. Furthermore, it is stated in the cited paper that the majority of the energy at the internetwork bright points of the solar granules does not transfer to higher layers of Sun. This suggests that the energy loss from bright points in the solar granules' internetwork region is rather high in the chromospheric layer. The time period of the wave damping is longer than the length of the damping time in the oscillations, according to the current study on the mechanism of wave dissipation in different layers of the sun and the network and internetwork bright points of the chromosphere. It has also been demonstrated that the time period of the wave damping is greater than the length of the damping time in the oscillations of the bright points of the granules' network region, which is the source of the most energy loss in this layer.
کلیدواژهها [English]
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