Zongjun Ning

Small-scale oscillations in a quiescent prominence observed by HINODE/SOT Prominence oscillations

Context. Investigations of the behavior of small-scale threads can provide an alternative approach to studying prominence dynamics and understanding its origin and nature. Aims. The behavior of threads are analyzed in a quiescent prominence, including drifting and both the horizontally and vertically oscillating motions. These indicate waves in the solar prominence. Methods. We used the Ha images at a setting wavelength of +0.076 angstrom. A quiescent prominence was observed by HINODE/SOT on 2008 January 15 for about 3 h in total. Results. Consistent with previous findings, prominences show numerous thread-like structures. Some threads clearly exhibit both vertically and horizontally oscillatory motions, while others are only drifting. Complicated cases show both drifting and oscillatory motions simultaneously. In the upper part of the prominence, the threads are oscillating independently of each other. We find that three threads oscillate with the same phase for at least two periods. The oscillations seem to be strongly damped since they disappear after a few periods. The maximum number of observed periods is 8 in our observations. In the lower part of the prominence, however, the different threads have a mixed character with the individual oscillatory motions unstable for one entire period. Most oscillatory motions will disappear after a half period or less, while the new oscillatory motions are excited nearby. A 5-min period is predominant, and the oscillating amplitudes show an average value of +/- 3.5 km s(-1). We find some upflows in the spicule layer, and they appear to transport the mass from photosphere ( or spicules themselves) to the prominence. These upflows have an average velocity amplitude of 0.8 km s(-1). Conclusions. The threads exhibit three distinct behaviors. The first is only drifting, the second is typically oscillating, and the third shows both characteristics. There are no substantial differences between the periods of horizontally and vertically oscillating threads in this prominence.

Imaging and spectral observations of quasi-periodic pulsations in a solar flare

We explore the quasi-periodic pulsations (QPPs) in a solar flare observed by Fermi Gamma-ray Burst Monitor, Solar Dynamics Observatory, Solar Terrestrial Relations Observatory, and Interface Region Imaging Spectrograph (IRIS) on 2014 September 10. QPPs are identified as the regular and periodic peaks on the rapidly varying components, which are the light curves after removing the slowly varying components. The QPPs display only three peaks at the beginning on the hard X-ray emissions, but 10 peaks on the chromospheric and coronal line emissions, and more than seven peaks (each peak corresponds. to a type III burst on the dynamic spectra) at the radio emissions. A. uniform quasi-period of about 4 minutes is detected among them. AIA imaging observations exhibit that the 4-minute. QPPs originate from the flare ribbon. and tend to appear on the ribbon front. IRIS spectral observations show that each peak of the QPPs tends to a broad line width and a red Doppler velocity at C I, O IV, Si IV, and Fe XXI lines. Our findings indicate that the QPPs are produced by the non-thermal electrons that are accelerated by the induced quasi-periodic magnetic reconnections in this flare.

MULTIWAVELENGTH OBSERVATIONS OF A PARTIALLY ERUPTIVE FILAMENT ON 2011 SEPTEMBER 8

In this paper, we report our multiwavelength observations of a partial filament eruption event in NOAA active region 11283 on 2011 September 8. A magnetic null point and the corresponding spine and separatrix surface are found in the active region. Beneath the null point, a sheared arcade supports the filament along the highly complex and fragmented polarity inversion line. After being activated, the sigmoidal filament erupted and split into two parts. The major part rose at the speeds of 90

BEHAVIOR OF THE SPINES IN A QUIESCENT PROMINENCE OBSERVED BY HINODE/SOT

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Microwave and Hard X-Ray Spectral Evolution in Two Solar Flares

150 km s

Different behaviors between microwave and hard X-ray spectral hardness in two solar flares

^{-1}

EXPLOSIVE CHROMOSPHERIC EVAPORATION IN A CIRCULAR-RIBBON FLARE

before reaching the maximum apparent height of

Quasi-periodic pulsations with periods that change depending on whether the pulsations have thermal or nonthermal components

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INVESTIGATING THE CONDITIONS OF THE FORMATION OF A TYPE II RADIO BURST ON 2014 JANUARY 8

115 Mm. Afterwards, it returned to the solar surface in a bumpy way at the speeds of 20

Doppler Shift Oscillations from a Hot Line Observed by IRIS

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