Solar type III radio bursts are crucial indicators of energetic electron activity in the solar corona and interplanetary space. Our assessment of 43 interplanetary type III bursts, recorded by the FIELDS instrument on board the Parker Solar Probe during Encounters 05 to 11, has led to significant and complex findings. We have analyzed time profile features across a frequency range of 19–0.5 MHz, revealing dependencies on frequency and providing insights into duration, burst speeds, bandwidths, and drift rates. This novel analysis has unveiled a spectral index of −0.63 ± 0.04 for rise, −0.69 ± 0.03 for decay time, and −0.68 ± 0.03 for the total duration. We have determined the average electron beam velocities for front, middle, and back as 0.15c, 0.13c, and 0.08c, respectively. Our findings show that faster electron beams generate emissions with shorter duration. The average ratio of the front-to-back velocity is 1.87, and the ratio of front-to-middle velocity is 1.23. We have also discovered a strong relationship between burst duration with rise, peak, and decay times, particularly pronounced with decay time (correlation coefficient = 0.95). This indicates that the entire temporal profile, including rise, peak, and decay phases, collectively contributes to event duration and is not solely influenced by external factors like plasma conditions or electron beam dynamics but also by internal burst processes. These complex findings shed light on the physical mechanisms governing burst dynamics, revealing intricate interactions between electron beam characteristics and observed temporal and spectral traits of type III solar radio bursts.

中文翻译：

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使用帕克太阳探测器进行 III 型太阳射电爆发的时间剖面研究


太阳 III 型射电爆发是日冕和行星际空间中高能电子活动的重要指标。我们对 43 次行星际 III 型爆发的评估（由帕克太阳探测器上的 FIELDS 仪器在遭遇 05 至 11 期间记录）得出了重要而复杂的发现。我们分析了 19-0.5 MHz 频率范围内的时间剖面特征，揭示了对频率的依赖性，并提供了对持续时间、突发速度、带宽和漂移率的深入了解。这项新颖的分析揭示了上升时间的光谱指数为-0.63 ± 0.04，衰减时间的光谱指数为-0.69 ± 0.03，总持续时间的光谱指数为-0.68 ± 0.03。我们确定前、中、后的平均电子束速度分别为 0.15c、0.13c 和 0.08c。我们的研究结果表明，更快的电子束产生的发射持续时间更短。平均前后速度比为1.87，前后速度比为1.23。我们还发现突发持续时间与上升时间、峰值时间和衰减时间之间存在很强的关系，特别是与衰减时间相关（相关系数 = 0.95）。这表明整个时间剖面，包括上升、峰值和衰减阶段，共同影响事件持续时间，并且不仅受到等离子体条件或电子束动力学等外部因素的影响，而且还受到内部爆发过程的影响。这些复杂的发现揭示了控制爆发动力学的物理机制，揭示了电子束特征与观察到的 III 型太阳射电爆发的时间和光谱特征之间复杂的相互作用。