Connection Between Chromospheric Events and Photospheric Dynamics

Abstract

We analyzed chromospheric events and their connection to oscillation phenomena and photospheric dynamics. The observations were done with the New Solar Telescope of Big Bear Solar Observatory using a broad-band imager at the wavelength of a TiO band and FISS spectrograph scanning Ca II and Hα spectral lines. The event in Ca II showed strong plasma flows and propagating waves in the chromosphere. The movement of the footpoints of flux tubes in the photosphere indicated flux tube entanglement and magnetic reconnection as a possible cause of the observed brightening and waves propagating in the chromosphere. An upward propagating train of waves was observed at the site of the downflow event in Hα. There was no clear relationship between photospheric waves and the Ca II and Hα events. Our observations indicate that chromospheric waves that were previously thought to originate from the photosphere may be generated by some events in the chromosphere as well.

Multiwavelength Studies of MHD Waves in the Solar Chromosphere

“…in as little as a few seconds (Figure 3), diffraction-limited narrowband imaging of deep absorption line cores at frame rates exceeding 40 s −1 , and spectral resolutions ( λ δλ ) exceeding 500 000 at wavelengths covering the optical through to the near-infrared. However, even with these powerful telescopes employing modern detectors and instrumentation, there is clear evidence to suggest that there are still lower-atmospheric phenomena manifesting below our currently imposed resolution limits (von Uexkuell & Kneer 1995;Lagg et al 2007;Jess et al 2008a;Cauzzi et al 2008Cauzzi et al , 2009Socas-Navarro et al 2009;Vourlidas et al 2010;Andić et al 2013). Thus, for the last number of years there has been an impetus placed on further developing the spatial, temporal and spectral resolutions of our ground-and space-based solar facilities.…”

Spectral Observations of Ellerman Bombs and Fitting With a Two-Cloud Model

“…FISS is an imaging spectrograph that adopts an Echelle disperser with field-scanning method, with which twodimensional spectra and images of dual spectral bands (Hα and Ca II 8542 Å) can be acquired simultaneously (Chae et al 2013a). FISS can probe into the physical processes in the photosphere and chromosphere, including plasma flows and oscillations in various phenomena, like fibrils, prominence, and EBs (Anđić et al 2013;Chae et al 2013b;Cho et al 2013;Maurya et al 2013;Park et al 2013;Yang et al 2013). Using FISS, we obtained Hα and Ca II 8542 Å spectra with high spatial and spectral resolution for a target area near the pores in NOAA 11765 on 2013 June 6.…”

Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

“…The authors undertook Fourier and Hilbert transformations of the TiO time series related to MBPs, in order to extract the amplitude and phase relationships of the embedded oscillations, and suggested that the detected wave motion is likely to be too complex to be generated by a single oscillatory source. Nevertheless, Andić et al [2013] provided direct evidence for the presence of upwardly propagating wave trains in the immediate vicinity of red-shifted (i.e., downflowing) material, suggesting the phase velocities of the magneto-acoustic wave phenomena were significantly higher than 5 km s −1 at the photospheric layer.…”

“…More recently, Andić et al [2013] employed broadband TiO images obtained using the NST to examine the connection between photospheric oscillations and the dynamic motions of smallscale magnetic flux concentrations. The TiO filter used is centred on an absorption band of molecules around 7056.8 Å (incorporating a 10 Å filter width), and thus averages over all inherent absorption and continua contributions, causing the resulting images to be only weakly dependent on the properties of individual spectral lines.…”