NSWP: Improving Quantitative Modeling of High-latitude Electrojet Conductivities during Magnetic Storm and Substorm Time

该项目旨在通过开发干扰条件下电喷射电导率的精确模型来提高空间天气预报能力。在强烈的地磁活动期间，沿着磁力线的大电流可以诱导形成强电喷流、等离子体不稳定和湍流。这种湍流引起强烈的异常电子加热和非线性输运，显著影响e区电导率。现有的电离层模型不包括这些影响。这限制了他们准确模拟磁暴和亚暴的能力，而这对空间天气预测至关重要。因此，本项目的目标是开发电离层电导模块，以预测磁暴和亚暴期间的非线性电流和异常电子加热。该模块将由一个查找表和/或解析表达式组成，它将返回一系列海拔、纬度、驱动电场、等离子体和中性大气条件下的e区电导率矩阵。项目将承担三个主要任务：(1)电子异常加热和非线性电流的定量建模；(2)建立考虑湍流效应的电导率数据库；(3)在现有磁层和电离层模拟代码和模型中测试修正后的电导率。三维e区湍流的超级计算机模拟将结合现代理论分析来确定加热和电导率。电子加热的预测将使用非相干散射雷达和火箭数据进行验证，而预测的电离层场和电流将使用磁力计和超级数据进行测试。为了使结果有用和可用，它们将被合并到lyon - federder - mobary （LFM）磁层模拟代码和磁层-电离层-热层模型（CMIT）中，这两个代码被磁层/电离层界广泛使用。升级后的LFM和CMIT的结果将与未修改的代码和观测结果进行测试。需要解决的特殊科学问题是：高纬度电离层对强对流电场的非线性响应是什么？为什么观测到的风暴时间跨极帽势通常比现有模型预测的要小？湍流引起的电导率变化是模型无法解释观测结果的主要原因还是全部原因？

The project aims to improve space weather prediction capabilities by developing an accurate model of electrojet conductivity under disturbed conditions. During periods of intense geomagnetic activity, large currents along the magnetic field lines can induce the formation of strong electrojets, plasma instabilities, and turbulence. This turbulence gives rise to intense anomalous electron heating and nonlinear transport which significantly affects the E-region conductivity. Existing ionospheric models do not include these effects. This limits their ability to accurately model magnetic storms and substorms essential for space weather predictions. Accordingly, the objective of this project is to develop an ionospheric-conductance module which will predict nonlinear currents and anomalous electron heating during magnetic storms and substorms. This module will consist of a look-up table and/or analytic expressions which will return the E-region conductivity matrix for a range of altitudes, latitudes, driving electric fields, and plasma and neutral atmospheric conditions. The project will undertake three tasks: (1) quantitative modeling of anomalous electron heating and nonlinear currents; (2) creation of a conductivity database which accounts for turbulent effects; and (3) testing the modified conductivities in existing magnetosphere and ionosphere simulation codes and models. Supercomputer simulations of 3D E-region turbulence combined with modern theoretical analyses will be applied to determine the heating and conductivities. The predictions of electron heating will be validated using incoherent scatter radar and rocket data, while the predicted ionospheric fields and currents will be tested against magnetometer and SuperDarn data. In order to make the results useful and available, they will be incorporated into the Lyon-Fedder-Mobary (LFM) magnetosphere simulation code and the magnetosphere-ionosphere-thermosphere model (CMIT), two codes that are widely used by the magnetosphere/ionosphere community. The results of the upgraded LFM and CMIT will be tested against the unmodified codes and observations. Particular science questions to be addressed are: What is the nonlinear response of the high-latitude ionosphere to strong convection electric fields? Why is the observed storm-time cross-polar-cap potential often smaller than that predicted by existing models? Do the turbulence generated changes in conductivities mostly or fully account for the reason that models fail to account for observations?