论文标题
下太阳大气中参数衰减不稳定的证据
Evidence for Parameteric Decay Instability in the Lower Solar Atmosphere
论文作者
论文摘要
我们发现在下部太阳大气中首次观察参数衰减不稳定性（PDI）的证据。具体而言，我们发现太阳过渡区域附近的密度波动的功率谱类似于速度波动的功率谱，但频率轴的扩大约为两个。这些结果来自对极性冠状孔的过渡区域中界面区域成像光谱仪（IRIS）观察到的SI IV线的分析。我们还发现，密度波动的径向速度约为75 km/s，并且在过渡区域中，速度波动的速度波动的速度分别为250 km/s，估计速度为250 km/s。理论计算表明，这种频率关系与观察到区域的血浆条件的PDI预期的关系一致。这些测量表明，在过渡区域中，声波与Alfvén波之间存在相互作用，这是参数衰减不稳定性的证据。
We find evidence for the first observation of the parametric decay instability (PDI) in the lower solar atmosphere. Specifically, we find that the power spectrum of density fluctuations near the solar transition region resembles the power spectrum of the velocity fluctuations, but with the frequency axis scaled up by about a factor of two. These results are from an analysis of the Si IV lines observed by the Interface Region Imaging Spectrometer (IRIS) in the transition region of a polar coronal hole. We also find that the density fluctuations have radial velocity of about 75 km/s and that the velocity fluctuations are much faster with an estimated speed of 250 km/s, as is expected for sound waves and Alfvén waves, respectively, in the transition region. Theoretical calculations show that this frequency relationship is consistent with those expected from PDI for the plasma conditions of the observed region. These measurements suggest an interaction between sound waves and Alfvén waves in the transition region that is evidence for the parametric decay instability.
