M-I Coupling: A Model for Ionospheric Velocity Structure in the High-Latitude F Region

M-I耦合：高纬F区电离层速度结构模型

• 批准号: 0101118
• 负责人: Marc Hairston
• 金额: $ 21万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0101118&HistoricalAwards=false
• 关键词: Coupling; Model; Ionospheric; Velocity; Structure

As coupled magnetospheric, ionospheric and thermospheric models mature it is increasingly apparent that Joule heating may take place over a wide variety of spatial scale sizes. Current models used for space weather estimate Joule heating rates by using average bulk plasma flow velocities (Vb) in large-scale high-latitude convection patterns. However, recent studies suggest that structure in the ion drift over smaller scale sizes of 10 to 100 km may change the estimated Joule heating rate by more than a factor of 2. This proposal will use data from the Dynamics Explorer-2 satellite and from the DMSP satellites to describe the average and maximum amplitude of velocity structure (AV) at high latitudes as a function of position, season, solar cycle and geomagnetic activity. Thus, Joule heating rates previously calculated using only the average bulk flow rate Vb of the plasma will be improved to become a function of Vb + AV. The data description will be cast in the form of a model that functionally describes the magnitude of the velocity structure in terms of the bulk flow so that these refined estimates of Joule heating rates can be easily used both in thermospheric models and as boundary conditions for coupling magnetospheric models with the ionosphere. A first order dependence of the model on magnetic activity will allow a better specification of the high latitude thermosphere and ionosphere for space weather applications.

随着磁层、电离层和热层耦合模型的成熟，越来越明显的是，焦耳加热可能发生在各种各样的空间尺度上。目前用于空间天气的模型通过使用大规模高纬度对流模式中的平均体等离子体流速（Vb）来估计焦耳加热率。然而，最近的研究表明，在10至100公里的较小尺度上，离子漂移的结构可能会改变估计的焦耳加热速率超过2倍。这项建议将利用来自动力学探索者-2号卫星和DMSP卫星的数据，描述高纬度地区速度结构的平均和最大幅度，作为位置、季节、太阳周期和地磁活动的函数。因此，先前仅使用等离子体的平均总体流率Vb计算的焦耳加热速率将被改进为Vb + AV的函数。数据描述将以一个模型的形式进行，该模型在功能上描述了整体流方面的速度结构的大小，以便焦耳加热率的这些精确估计可以很容易地用于热层模型，并作为磁层模型与电离层耦合的边界条件。该模型对磁活动的一阶依赖性将使空间气象应用能够更好地说明高纬度热层和电离层。