Whistler Mode Radio Sounding of Electrons, Ions and Density Irregularities in the Inner Magnetosphere from 90 to 5000 km

在磁层和电离层研究中，确定内磁层等离子体的密度和组成在很大程度上是一个未开发的领域。这项为期三年的研究计划将利用最近开发的哨声模式（WM）无线电探测技术和新一代空间和地面实验数据，调查90至5000公里范围内磁层内部等离子体密度、离子组成和密度不规则性。提出了四个研究项目：(1)利用IMAGE卫星上无线电等离子体成像仪（RPI）的WM无线电探测数据，测量沿磁场线的冷等离子体密度（Ne）、离子组成（H+、O+、He+）和密度不规则性（10m ~ 10km尺度）与地球物理条件（如位置、当地时间、等离子体顶位置、地磁和太阳活动）的函数关系。(2)研究磁暴前、中、后磁暴中电子密度和离子组成沿磁力线的变化（损失和再填充）。(3)建立90- 5000 km范围内等离子体密度、离子组成和密度不规则性随地球物理条件变化的经验模型。(4)将WM探测结果与互补的地面探测（如电离层探空仪、磁力计）、原位探测（如DMSP、CHAMP、CRESS、POLAR）和无线电探测（如自由空间模式下更高高度的RPI探测）相结合，增强和扩展经验模型，建立赤道高度以下磁层内等离子体密度和成分的新场向模型。这些经验模型将用于对磁层-电离层耦合的重要过程和机制获得新的认识，并用于空间天气预报。因此，这些结果在空间物理研究中具有广泛的应用前景。这项提案将资助一名研究生。

Determining the density and composition of plasma in the inner magnetosphere is a largely unexplored area of magnetospheric and ionospheric research. Using recently developed whistler mode (WM) radio sounding techniques and data from a new generation of space- and ground-based experiments, this three-year research program will investigate inner magnetospheric plasma density, ion composition and density irregularities from 90 to 5000km. Four research projects have been proposed: (1) Use WM radio sounding data from the Radio Plasma Imager (RPI) on the IMAGE satellite to measure the cold-plasma density (Ne), ion composition (H+, O+, He+) and density irregularities (10m to 10km scale size) along a magnetic field line as a function of geophysical conditions (e.g. location, local time, plasmapause position, geomagnetic and solar activity). (2) Study the variation (loss and refilling) of electron density and ion composition along geomagnetic field lines before, during, and after geomagnetic storms.(3) Build empirical models of plasma density, ion composition and density irregularities as functions of geophysical conditions along B0 from 90-5,000km. (4) Combine WM sounding results with those from complementary ground based (e.g. ionosonde, magnetometer), spacecraft based in situ (e.g. DMSP, CHAMP, CRESS, POLAR) and radio sounding (e.g. RPI sounding at higher altitude in free space modes) to augment and extend the empirical models and to build new field aligned models of the inner magnetospheric plasma density and composition up to equatorial altitudes.These empirical models will be used to gain new understanding into processes and mechanisms important to magnetosphere-ionosphere coupling and for use in space weather predictions. As a result these results should have broad application in space physics research. The proposal will support a graduate student.