Q. Zhang, Purple Mountain Observatory, zhangqm@pmo.ac.cn
  Z. Ning, Purple Mountain Observatory, ningzongjun@pmo.ac.cn
  H. Ji, Purple Mountain Observatory, jihs@pmo.ac.cn
  P. Chen, Nanjing University, chenpf@nju.edu.cn
  C. Xia, Leuven University, chun.xia@wis.kuleuven.be

This talk is divided into two parts. The first part is about longitudinal prominence oscillations. Using multi-wavelength observational data, we found longitudinal prominence oscillation on 2007 February 8. The initial amplitude, velocity amplitude, period, and damping time are 24 Mm, 40 km/s, 52 minutes, and 133 minutes. The oscillation above the limb lasted for ~3.5 cycles. The oscillation might be the precursor for the following flare and CME. Numerical simulations show that the restoring force of the oscillation is gravity of the prominence. Radiative loss and thermal conduction are insufficient to account for the quick damping. A parameter survey is performed to further investigate the triggering mechanism, restoring force, and damping mechanism of the oscillations. The second part is partial filament eruption. Using multi-wavelength observational data, we found partial filament eruption on 2011 September 8. Due to flux emergence or inner tether cutting, the filament erupted and split into two parts during its eruption, which produced an M-class flare. The major part rose to the maximum height before returning to the solar surface. In other words, it experienced failed eruption that could be observed in Ha, UV, and EUV. The runaway part, however, escaped the corona and produced a weak CME, possibly along open magnetic field lines. We discuss the potential significance for space weather prediction.