Study of Auroral Radio Emissions from Alaska: Continued Observations and Data Analysis

尽管人们在射电波长上研究了极光的强度，但地面测量在几百千赫(甚低频实验的上限范围)和几十兆赫(里米计的工作频率)之间仍然存在差距。许多地面观测表明，极光在这个频率范围内产生了排放，但观测结果参差不齐，这些排放的性质甚至是否存在仍不确定。有一些理论工作证明使用地面仪器调查极光发射是合理的，但还需要更系统的观测，为进一步的理论进展奠定基础。根据国家科学基金会以前的一笔赠款，开发了一台基于个人计算机的仪器，用于监测来自偏远地点的0.1-5兆赫无线电波，并在一个冬季内运行，对数据进行了初步分析，并编写或出版了关于这一相关主题的出版物。明年，我们建议继续使用改进版的仪器从阿拉斯加收集无线电数据。我们还提出了完成去年数据和来年数据分析的三个具体计划。下一个研究年的目标是：1)为消除地面可从极光观测到的低频/中频/高频辐射的存在和(或)性质方面的不确定性提供一个坚实的开端；2)确定在北半球使用基于个人计算机的无线电接收器的方法是否显示出在频率范围内对极光发射进行长期观测的前景；以及3)完成几个具体的数据分析目标，这些目标可以通过去年收集的数据实现，并将通过下一年的数据得到加强。

Despite the intensity with which the aurora has been studied at radio wavelengths, there remains a gap in the ground measurements between a few hundred kiloHertz, the upper range of VLF experiments, and a few tens of megaHertz, at which riometers operate. A number of ground observations indicate that emissions are generated by the aurora in this frequency range, but the observations are spotty, and the nature and even the existence of these emissions remains uncertain. There is some theoretical work justifying the investigation of auroral emissions using ground- based instrumentation, but more systematic observations are needed to lay the groundwork for further theoretical progress. Under a previous NSF grant, a PC-based instrument for monitoring 0.1-5 MHz radio waves from remote sites has been developed and operated for one Winter, a preliminary analysis of the data has been done, and publications on this related subjects have been prepared or published. In the next year, we propose to continue collecting radio data from Alaska with an improved version of the instrument. We further propose three specific plans for completing the analysis of last year's data and the data from the upcoming year. The goals of the further year of study are: 1) to provide a solid start towards clearing up the uncertainty regarding the existence of and/or natures of LF/MF/HF emissions observable on the ground from aurorae; 2) to determine whether the method of using PC-based radio receivers in the Northern Hemisphere shows promise for longer-term observations of auroral emissions in the frequency range; and 3) to complete several specific data analysis goals which are achievable with data collected last year, and which will be enhanced by a further year of data.