Subjects: Astronomy >> Astrophysical processes submitted time 2022-09-19 Cooperative journals: 《天文研究与技术》
Abstract： L-band solar radio burst is a potential influencing factor of navigation system instability, through the L-band precision solar current volume monitoring can be found in real time solar burst interference navigation events, for this reason Yunnan Astronomical Observatory headquarters intends to establish an L-band multi-frequency point solar radio monitoring system. An effective assessment of the radio environment is essential for the stable access to observational data from the monitoring system. This paper introduces the radio monitoring readiness study of the monitoring platform, and conducts a 100-hour test of the L-band radio environment in the Fenghuangshan area of the Headquarters of the Yunnan Astronomical Observatory. In this paper, an algorithm based on the improved threshold of Simple Thresholding algorithm and CUSUM algorithm is proposed, and 7 radio passbands with less 5MHz radio interference between the Beidou B1, B2, B3 frequency points, GPS L1 and L2 frequency points are selected, namely 1551MHz~1555 MHz, 1596MHz~1600MHz, 1161MHz~1165MHz, 1221MHz~1225MHz, respectively. 1246MHz~1250MHz, 1291MHz~1295MHz, 1231MHz~1235MHz, its cleanliness rates are 98.329%, 98.301%, 98.315%, 98.335%, 98.224%, 97.650%, 98.260%, all of which meet the needs of solar observation. It provides a basis for the next step of receiver design and signal processing.
Subjects: Astronomy >> Astrophysical processes submitted time 2020-11-19 Cooperative journals: 《天文研究与技术》
Abstract：太阳高能活动爆发与活动区内的电流结构有着密切的联系，安培（Ampere）定律j_z=〖1/μ_0 (∇×B)〗_z是测量活动区内视向电流密度的理论基础。由于实测的矢量磁场中不可避免地存在随机噪声，因此，应用安培定律的不同形式计算的电流密度存在显著的差异。为了比较不同形式计算结果的差异并从中探索一种实用的电流计算方法，基于太阳动力学天文台(Solar Dynamic Observatory,SDO)/HMI(Helioseismic and Magnetic Imager)在2011年2月15日测量的活动区AR11158的矢量磁图，运用安培定律的微分算法和积分算法分别计算了活动区内视向电流密度的分布图。结果显示，微分算法获得的视向电流密度j_z分布图受随机噪声的影响要远比积分算法获得的结果大，电流分布图中的电流结构没有积分算法获得的结果清晰。另外，在扩大积分环路半径的情况下，所计算的电流分布图里的噪声信号快速降低，从而使计算的视向电流分布图中的电流结构更清晰。但是当继续扩大积分环路半径时，在获得清晰电流分布图的同时，电流分布图的部分精细结构也随之失真。该研究结果论证了适当扩大积分环路计算视向电流分布图可以降低计算结果受随机噪声的影响，从而获得清晰真实的视向电流分布图，但是积分路径的半径过大在消除噪声影响的同时会丢失电流分布中的一些精细结构。因此在实际计算电流的过程中，应该利用高分辨率的矢量磁图，选定合适的积分路径运用安培定律的积分算法来计算活动区的视向电流，从而帮助我们探索耀斑爆发与活动区内电流结构的关系。
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