Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden and School of Physics, University of Sydney, New South Wales 2006, Australia.
Phys Rev Lett. 2013 Sep 20;111(12):121101. doi: 10.1103/PhysRevLett.111.121101. Epub 2013 Sep 17.
Localized Langmuir waves are commonly observed in space plasmas and are a potential source of radio waves. Using electric field data from STEREO, it is shown that these localized Langmuir waves are eigenmodes of density wells estimated independently. An analytic model is developed for the eigenmode frequencies. The inferred depths and widths of the density wells typically only allow the zeroth-order Langmuir eigenmode to form, explaining the preponderance of single-peaked waveforms. More complicated waveforms are shown to be consistent with single eigenmode solutions of more complicated density profiles. The inferred depth of the density well increases with Langmuir wave intensity, consistent with the ponderomotive force but not wave packet collapse.
局域化朗缪尔波在空间等离子体中很常见，是无线电波的潜在来源。利用STEREO 的电场数据，表明这些局域化朗缪尔波是独立估计的密度阱本征模。为此本征模频率建立了一个解析模型。推断出的密度阱的深度和宽度通常只允许形成零阶朗缪尔本征模，这解释了单峰波形占主导的原因。更复杂的波形与更复杂的密度分布的单本征模解一致。密度阱的推断深度随朗缪尔波强度的增加而增加，这与压强势一致，但与波包塌缩无关。
