声波场强非均匀分布对日震时距观测的影响
Influence of Non-Uniform Distribution of Acoustic Wavefield Strength on Time-Distance Helioseismology Measurements
摘要：
通过分析数值模拟的太阳振荡数据，研究了声波振幅的非均匀分布、声源强度和声速扰动对时距日震学方法测量的声波走时偏移的影响。据发现，对于短距离，在太阳黑子中的声源的非均匀分布所造成的平均旅行时移的贡献可能是可比的（但小于）的贡献，从音速扰动在太阳黑子，它具有相反的符号的声速效应。这种效应可能会导致一些低估的负声速扰动的太阳黑子就在表面之下，这是发现在以前的时间距离日震学推断。这种效应不能通过人为地增加太阳黑子的振荡幅度来纠正。对于较大的时距环隙，波场的非均匀分布对平均走时没有显著影响，从而得到声速反演结果。被用来确定太阳黑子下的质量流的测量的旅行时间差也可以被这种效应系统地改变，但只是在一个微不足道的幅度。
英文摘要：
By analyzing numerically simulated solar oscillation data, we study the influence of non-uniform distribution of acoustic wave amplitude, acoustic source strength, and perturbations of the sound speed on the shifts of acoustic travel times measured by the time-distance helioseismology method. It is found that for short distances, the contribution to the mean travel time shift caused by non-uniform distribution of acoustic sources in sunspots may be comparable to (but smaller than) the contribution from the sound speed perturbation in sunspots, and that it has the opposite sign to the sound-speed effect. This effect may cause some underestimation of the negative sound-speed perturbations in sunspots just below the surface, that was found in previous time-distance helioseismology inferences. This effect cannot be corrected by artificially increasing the amplitude of oscillations in sunspots. For large time-distance annuli, the non-uniform distribution of wavefields does not have significant effects on the mean travel times, and thus the sound-speed inversion results. The measured travel time differences, which are used to determine the mass flows beneath sunspots, can also be systematically shifted by this effect, but only in an insignificant magnitude.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
