标题： 磁性模型在罗Ap星声模中的应用 显示英文标题

标题： A magnetic model for acoustic modes in roAp stars

摘要： 快速振荡、特殊的A型（roAp，或温度较低的化学特殊型，CP）星中p模激发的机制尚不清楚。观测强烈表明，roAp星中的声学模式与恒星磁场存在因果关系。我们提出，平均磁场形状的小幅波动会驱动磁声波，这些波在这些恒星中被观测为p模。roAp星的动力学边缘区域是一个无力场的球壳。当强耦合到磁场时，无力场等离子体可以围绕其平均磁场能量的最小值振动。我们描述了在这种具有开放边界的球壳中能量最小值的稳定本征模态。由此产生的振荡的波数、频率和能量与roAp星中p模的观测结果一致。我们的恒星p模振荡磁性模型并未引入对流或opacity机制。我们还提出了这类缺乏通常所需的对流的磁性恒星可能存在非线性发电机的可能性。 显示英文摘要

摘要： The mechanism for excitation of p-modes in rapidly oscillating, peculiar A (roAp, or cool chemically peculiar, CP) stars is unknown. Observations strongly suggest that acoustic modes in roAp stars are causally linked to the stars' magnetic field. We propose that small fluctuations in the shape of the mean magnetic field drive magnetosonic waves, which are observed as p-modes in these stars. The dynamic edge region of roAp stars is a force-free spherical shell. When strongly coupled to the magnetic field, a force-free plasma can oscillate about a minimum in its mean magnetic energy. We describe the stable eigenmodes for this energy minimum in a spherical shell with an open boundary. The wavenumbers, frequencies, and energies of resulting oscillations are consistent with observations of p-modes in roAp stars. Our magnetic model for p-mode oscillations in stars does not invoke convection or opacity mechanisms. We also suggest the possibility of a nonlinear dynamo for such magnetic stars, which lack the convection needed for the usual (-( dynamo.