CAREER: Impact of Plasma Species, Mixing and Ionization Fraction on Drift-Wave Turbulence and Transport

该奖项的部分资金来自2021年美国救援计划法案（公法117-2）。该职业奖支持使用实验和计算方法相结合的等离子体湍流研究。 宇宙中99%的可见物质都是等离子体，这是一种物质状态，通常是在气体被加热到足够高的温度时产生的，以将电子从原子中剥离，从而产生带电粒子云。实验和观察表明，等离子体可以是湍流的，表现出与在流体中观察到的相似的动力学。在研究等离子体中的湍流时，通常假设等离子体仅由电子和一种离子组成，并且这些云100%电离。然而，在现实中，等离子体并没有完全电离，中性粒子的存在会影响湍流的动力学。 此外，等离子体通常包含多个离子种类，这意味着单个离子可以具有不同的质量和电荷。即使是小浓度的多离子物种也会对湍流产生非线性影响，而这些方面在当前的模型和实验中往往被忽略。更好地了解混合离子种类等离子体的作用以及中性粒子的影响，可以提供对空间天气和核聚变发电厂设计的见解。 除了科学范围外，该奖项还支持创建一个可持续的K5计划，该计划旨在引入与等离子体和湍流相关的主题。该项目将使用LArge等离子体设备（LAPD），这是加州-洛杉矶大学基础等离子体科学设施内的线性磁化等离子体设备，用于研究漂移波等离子体湍流。LAPD有可能改变中性压力以及等离子体密度和温度，从而有效地允许改变电离比和中性等离子体分数。通过专门扫描电子温度、密度和中性密度，实验将测量湍流和等离子体流的变化。这些扫描将针对不同的等离子体物质以及最终混合的等离子体物质重复进行。为了更好地解释实验，将使用流体等离子体代码爱马仕来自洽地计算存在中性物质时的湍流和等离子体轮廓。模型和实验的结合将使我们能够更好地了解模型是否能够捕捉到各种（混合）等离子体物种和中性粒子的动态，或者模型是否需要进一步开发。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持的。

This award is funded in part under the American Rescue Plan Act of 2021 (Public Law 117-2). This CAREER award supports a study of plasma turbulence using a combination of experimental and computational approaches. 99% of all visible matter in the universe is a plasma, a state of matter commonly created when a gas is heated to high enough temperatures to strip electrons away from the atoms, creating a cloud of electrically charged particles. Experiments and observations have shown that plasmas can be turbulent, demonstrating similar dynamics to that observed in fluids. When studying the turbulence in plasmas, it is often assumed that plasmas only consist of electrons and one ion species, and these clouds are 100% ionized. However, in reality, plasmas are not fully ionized and the presence of neutral particles can influence the dynamics of turbulence. Moreover, plasmas often contain multiple ion species, which means that the individual ions can have a different mass and charge. Even small concentrations of multiple ion species can have non-linear effects on turbulence and these aspects are often neglected in current models and experiments. Better understanding of the role of mixed-ion species plasmas as well as the influence of neutral particles can provide insights into space weather and the design of nuclear fusion power plants. In addition to the scientific scope, this award supports creation of a sustainable K5 program built to introduce topics related to plasmas and turbulence.This project will use the LArge Plasma Device (LAPD), a linear magnetized plasma device within the Basic Plasma Science Facility at the University of California - Los Angeles, to study drift-wave plasma turbulence. LAPD has the possibility to change the neutral pressure as well as the plasma density and temperature, thus effectively allowing alteration of the ionization ratio and the neutral to plasma fraction. Through dedicated scans of electron temperature, density and neutral density, the experiments will measure the changes in turbulence and plasma flows. These scans will be repeated for different plasma species and eventually mixed plasma species. To better interpret experiments, a fluid plasma code HERMES will be used to self-consistently calculate turbulence and plasma profiles in the presence of neutral species. The combination of modeling and experiments will allow a better understanding of whether the models can capture the dynamics of various (mixed) plasma species and neutrals, or whether the models need to be further developed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.