Energy Transfer in Collisionless Astrophysical Plasmas

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。本研究主要集中在等离子体物理的两个前沿领域，其中粒子模拟（PIC）可以帮助阐明等离子体中能量转移的基本原理：（1）受无碰撞吸积盘的启发，我们将研究离子和电子之间的能量转移是否可以在离子温度远高于电子温度的各向异性双温等离子体中发生。电子-质子耦合通过波产生的大量剪切流，韦伯，双流，和其他碰撞MHD不稳定性将被考虑。快于哥伦布耦合的存在或不存在将严格限制的可行性的两个温度的吸积流，如平流为主的吸积流作为一个范例的辐射效率低下的吸积流的一些星系核，和状态的X射线双星。(2)受电流驱动的韦伯型不稳定性在天体物理学驱动的冲击和激光驱动的冲击中的基本作用的启发，研究人员将研究和比较这两种类型的形成和磁场产生。本科生将参与数据分析和可视化。对罗切斯特大学正在进行的本科生广播节目的支持将得到扩大。该节目突出了一些科学和工程的发展，每两周一次，但重复3-4分钟的广播到罗切斯特地区。 乌尔都大学正在为物理学、天体物理学和工程学的研究生和本科生开设PIC模拟课程。关于PIC的讲座也将在UR DOE聚变科学中心组织的暑期学校中进行。该项目将产生新的教学材料，以展示PIC模拟如何应用于新的研究领域。该项目还将培养研究生和博士后研究人员在等离子体物理学，天体物理学和PIC模拟的跨学科专业知识。该提案已提交给NSF-DoE等离子体科学与工程合作伙伴关系联合征集08-589。该奖项由数学和物理科学理事会物理和天文科学司共同资助。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This research focuses on two frontiers of plasma physics where particle-in-cell (PIC) simulations can help elucidate underlying principles of energy transfer in plasmas: (1) Motivated by collisionless accretion disks, we will study whether a faster-than-Coulomb energy transfer between ions and electrons can occur in a two-temperature plasma with an anisotropic ion temperature much higher than the electron temperature. Electron-proton coupling via waves generated by bulk sheared flows, Weibel, two-stream, and other collisionless MHD instabilities will be considered. The presence or absence of a faster-than-Columb coupling will place rigorous constraints on the viability of two-temperature accretion flows such as advection dominated accretion flows as a paradigm for the radiatively inefficient accretion flows of some galactic nuclei, and states of X-ray binaries. (2) Motivated by the fundamental role of the current-driven Weibel-type instabilities in both astrophysically motivated shocks and laser-driven shocks, researchers will study and compare the formation and magnetic field generation in both types. Undergraduates will be involved in the data analysis and visualization. Support for an ongoing undergraduate radio show at the University of Rochester will be expanded. The show highlights a few science and engineering developments biweekly for a short, but repeated 3-4 minute broadcasts to the Rochester area. A course on PIC simulations is being developed at UR for graduate and undergraduate students from physics, astrophysics, and engineering. Lectures on PIC will also be given at the Summer Schools organized by the UR DOE Fusion Science Center. This project will generate new teaching materials to demonstrate how PIC simulations can be applied to new research areas. The project will also train graduate students and postdoctoral researchers with interdisciplinary expertise in plasma physics, astrophysics, and PIC simulations.This proposal was submitted to the NSF-DoE Partnership in Plasma Science and Engineering joint solicitation 08-589. This award is being funded jointly by the Divisions of Physics and Astronomical Sciences of the Mathematical and Physical Sciences Directorate.