标题： 使用Artemis-IV和NRH的高分辨率观测。 Ⅰ. 与Ⅳ型爆裂相关的窄带爆发现象 显示英文标题

标题： High resolution observations with Artemis-IV and the NRH. I. Type IV associated narrow-band bursts

摘要： 窄带爆发在微波到十米频段的动态频谱中表现为具有极短持续时间和极窄带宽的精细结构。 它们被认为标志着小尺度磁场重联。 我们分析了1999年6月30日至2010年8月1日期间由ARTEMIS-IV射电频谱仪观测到的27个带有窄带爆发的米波IV型事件。 我们检查了孤立窄带爆发以及尖峰组或链的形态特征。 这些事件由ARTEMIS-IV的SAO（10毫秒采样率）接收机在270-450 MHz范围内记录。 我们测量了大约12000个单独的窄带爆发、组和链的持续时间、频谱宽度和频率漂移。 尖峰源通过NRH成像用于2003年4月21日的事件。 固定频率下单个爆发的平均持续时间为约100毫秒，而瞬时相对带宽约为2%。 一些爆发有可测量的频率漂移，正或负。 尖峰通常以链条形式出现，这些链条在时间上（列链条）或频率上（行链条）紧密排列。 列链条具有与IIIb型爆发相似的频率漂移；大多数行链条表现出与纤维爆发类似的负漂移。 从NRH数据中，我们发现尖峰叠加在一个更大的、缓慢变化的背景成分之上。 它们的偏振方向与背景源相同，偏振度略高，约为65%，并且它们的大小约为总强度下的60%。 持续时间和带宽分布没有显示出任何明显的分组分离。 一些链条倾向于形成斑马纹、网纹、纤维或III型爆发家族的形式，这表明当用高分辨率观察时，这些爆发可能被解析为尖峰。 NRH数据显示，尖峰并非背景的波动，而是代表额外的发射，类似于从小尺度重联中预期的发射。 显示英文摘要

摘要： Narrow band bursts appear on dynamic spectra from microwave to decametric frequencies as fine structures with very small duration and bandwidth. They are thought to mark small scale magnetic reconnection. We analyzed 27 metric type-IV events with narrow band bursts observed by the ARTEMIS-IV radiospectrograph in 30/6/1999-1/8/2010. We examined the morphological characteristics of isolated narrow-band bursts and groups or chains of spikes. The events were recorded with the SAO (10 ms cadence) receiver of ARTEMIS-IV in the 270-450 MHz range. We measured the duration, spectral width, and frequency drift of ~12000 individual narrow-band bursts, groups, and chains. Spike sources were imaged with the NRH for the event of 21 April 2003. The mean duration of individual bursts at fixed frequency was ~100 ms, while the instantaneous relative bandwidth was ~2%. Some bursts had measurable frequency drift, positive or negative. Often spikes appeared in chains, which were closely spaced in time (column chains) or in frequency (row chains). Column chains had frequency drifts similar to IIId-bursts; most of the row chains exhibited negative drifts similar to fiber bursts. From the NRH data, we found that spikes were superimposed on a larger, slowly varying, background component. They were polarized in the same sense as the background source, with a slightly higher degree of polarization of ~65%, and their size was ~60% of their size in total intensity. The duration and bandwidth distributions did not show any clear separation in groups. Some chains tended to assume the form of zebra, lace stripes, fibers, or bursts of the type-III family, suggesting that such bursts might be resolved in spikes when viewed with high resolution. The NRH data indicate that the spikes are not fluctuations of the background, but represent additional emission such as what would be expected from small-scale reconnection.