• ELNAZ AMIRKHANLOU

      Articles written in Journal of Astrophysics and Astronomy

    • Waves propagation in network and inter-network bright points channels between the chromosphere and transition regions with IRIS observations

      SIMA ZEIGHAMI EHSAN TAVABI ELNAZ AMIRKHANLOU

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      The significance increase of the plasma temperature from the solar photosphere to the corona up to 1MK is still unresolved. One of the candidates for this issue is waves and instabilities in the solar plasma. It was suggested that the energy of these waves could heat the solar atmosphere to transition-region (TR) and corona. Despite many recent kind of researches about waves in the various solar dynamic structures, the reasons for the sudden rise of solar atmospheric temperature are still not enough. By using the Interface Region Imaging Spectrograph (IRIS) telescope observations, we investigate the waves in magnetic tubes such as UV bright points (BPs) at the boundary and inside the supper-granules. The Study of these dynamic structures, between the chromosphere and transition region, will impressively increase our information ofmass and energy transportation through interface region between the chromosphere and inner corona. The magnetic BPs are the faces of magnetic flux tubes that are associated with magnetic elements. The magnetic flux tubes expand upward and appear as bright grains that make up the chromospheric network. For investigating periodical behavior of these structures and various aspect of these oscillations, we analyze intensity oscillations individually in IRIS slit-jaw images at three filters included 2796 Å, 1400 Å and 1330 Å by the wavelet analysis method. The wavelet analysis of the intensity fluctuations of these points showed periods from 2 to 8 min, which are in order of the frequencies of the atmospheric pressure modes. For investigating wave propagation in these layers we also study the correlation of oscillations betweenchromosphere (2796 Å) and TR (1400 Å and 1330 Å) heights by cross wavelet method, and found that these heights correlate with periods between 2.5 and 5.5 min, with wave speeds from 30 to 200 km s$^{-1}$. Also, byextracting Si IV line, we determined the Doppler velocity of BPs in the network and inter-network as about $-$20 to $+$30 km s$^{-1}$ and $-$21 to $+$21 km s$^{-1}$, respectively. Our results suggest that the wave propagation along the magnetic flux tubes of upward-moving plasma in BPs have an important role in solar atmosphere heating.

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