• 한국초전도ㆍ저온공학회논문지
• /
• 제12권1호
• /
• pp.47-51
• /
• 2010

We already obtained magnetic behavior of superconducting Nb foil of linear type magnetic flux pump (LTMFP) by means of the FEM analysis. As well as, fundamental equations of pumping current were theoretically derived based on the pumping sequences according to the position of normal spot of the moving flux. In this paper, we experimentally investigated pumping performances of LTMFP with a wide range of traveling speed of magnetic field. In order to confirm the numerical and theoretical approaches, we explained the pumping characteristics of LTMFP by use of the calculation sequence of pumping current.

• 한국결정학회지
• /
• 제14권1호
• /
• pp.25-31
• /
• 2003

가속된 전자가 전자파의 원이다. 전자가 가속운동을 하면 그 전자에 의한 전장도 가속운동을 한다. 이 변하는 전장은 변하는 자장을 만들고 변하는 자장은 변하는 전장을 만드는 이 과정이 스스로 영구 반복된다. 이렇게 서로 연관되어 생성된 B와 E의 선들은 폐쇄된 loop들을 형성하면서 그 파원으로부터 속력 c로 멀어져 가는데 이 전장 및 자장을 전자파라 한다. 전자파의 모든 성질은 Maxwell의 식에서 수학적으로 추론된다.

• 천문학회보
• /
• 제39권2호
• /
• pp.98-98
• /
• 2014

Due to the simple vertical structure of magnetic field, pores can be exploited to study the transport of mechanical energy by waves along the magnetic field to the chromosphere and corona. For a better understanding of physics of pores, we have investigated chromospheric traveling features running across two merged pores from their centers at the speed about 55 km s-1, in the active region AR 11828. The pores were observed on 2013 August 24 by using high time, spatial, and spectral resolution data from the Fast Imaging Solar Spectrograph (FISS) of the 1.6 meter New Solar Telescope (NST). We infer a LOS velocity by applying the bisector method to the Ca II $8542{\AA}$ band and $H{\alpha}$ band, and investigate intensity and the line-of-sight velocity changes at different wavelengths and different positions at the pores. We find that they have 3 minutes oscillations, and the intensity oscillation from the line center is preceded by that from the core ($-0.3{\AA}$) of the bands. There is no phase difference between the intensity and the LOS velocity oscillations at a given wavelength. The amplitude of LOS velocity from near the core spectra is greater than that from the far core spectra. These results support the interpretation of the observed wave as a slow magnetoacoustic wave propagating along the magnetic field lines in the pores. The apparent horizontal motion and a sudden decrease of its speed beyond the pores can be explained by the projection effect caused by inclination of the magnetic field with a canopy.