Determining How Plasma Spontaneously Develops a Localized Hot Spot That Radiates X-rays and Produces Related Dramatic Phenomena

这个项目将在实验上探索等离子体的喷发行为，等离子体是一种带电离子和电子的气体，在类似于太阳和其他天体物理物体的条件下。这将通过在真空室中创建等离子体喷流并观察它们如何通过展示与太阳耀斑、天体物理伽马射线爆发和闪电X射线相关的突然和戏剧性的动态行为来喷发来完成。该研究计划将建造和使用新的诊断仪器，这些仪器将测量喷发行为，并测试当不稳定性试图中断等离子体喷流中的电流时，喷发会导致喷发的假设。该项目将与当地一所高中合作，让学生建造一种测量大气中带电粒子浓度的设备，从而激发人们对科学的兴趣，并鼓励他们从事等离子体物理或其他科学和工程领域的职业。该研究计划将确定一个看似良性的、寒冷的、相互碰撞的等离子体如何突然爆发并产生高能粒子、极端紫外线辐射、硬X射线和高频波。通过这样做，它将为美国国家科学基金会“宇宙之窗：多信使天体物理学时代”的宏大构想的目标做出贡献。将获得的知识和理解将应用于许多天体物理和实验室等离子体，如太阳耀斑、天体物理伽马射线暴、地面闪电的X射线暴和致密等离子体焦点装置。该计划将采用一种诊断良好的、可重复使用的实验室设备，在该设备中，最初较冷的等离子体会自发爆发并产生这些爆发。喷发过程的细节部分是通过可见光和极端紫外线的高速成像、通过X射线测量和通过哨声测量而确定的。将构建新的诊断方法，以测量喷发过程以前未量化的方面，如快速密度耗尽、快速粒子加热以及强大的局部电场和磁场的快速发展。这些诊断将成像与喷发相关的高度局部性的密度降低和温度上升。这些新的测量将使用先进的分析和数值方法进行建模。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will experimentally explore the eruptive behavior of a plasma, a gas of electrically charged ions and electrons, under conditions similar to those on the sun and in other astrophysical objects. This will be done by creating plasma jets in a vacuum chamber and observing how they can erupt by exhibiting sudden and dramatic dynamic behaviors mimicking the eruptive behaviors associated with solar flares, astrophysical gamma ray bursts, and X-rays from lightening. The research program will build and use new diagnostic instruments that will measure the eruptive behavior and test the hypothesis that eruption results when an instability tries to interrupt the electric current in a plasma jet. The project will engage a local high school with a vast majority of students from under-represented minority groups to have students build a device that measures the concentration of atmospheric charged particles, thereby motivating interest in science and encouraging them to pursue careers in plasma physics or other science and engineering fields. The research program will determine how a seemingly benign, cold, collisional plasma can suddenly erupt and generate a burst of energetic particles, extreme ultra-violet radiation, hard X-rays, and high-frequency waves. In doing so, it will contribute to the goals of NSF's "Windows on the Universe: The Era of Multi-Messenger Astrophysics" Big Idea. The knowledge and understanding to be gained will apply to many astrophysical and laboratory plasmas, such as solar flares, astrophysical gamma ray bursts, X-ray bursts from terrestrial lightning, and dense plasma foci devices. The program will employ a well-diagnosed, reproducible laboratory device in which an initially cold plasma spontaneously erupts and generates these bursts. The details of the eruptive process have been partly established via high-speed imaging of visible light and extreme ultraviolet radiation, via X-ray measurements, and via whistler wave measurements. New diagnostics will be constructed to measure previously unquantified aspects of the eruptive process such as rapid density depletion, rapid particle heating, and rapid development of strong localized electric and magnetic fields. These diagnostics will image highly localized reductions of density and increases of temperature associated with the eruption. These new measurements will be modeled using advanced analytic and numerical methods.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.