Quantifying the energy content of accelerated electron beams during solar eruptive events is a key outstanding objective that must be constrained to refine particle acceleration models and understand the electron component of space weather. Previous estimations have used in situ measurements near the Earth, and consequently suffer from electron-beam propagation effects. In this study, we deduce properties of a rapid sequence of escaping electron beams that were accelerated during a solar flare on 2013 May 22 and produced type III radio bursts, including the first estimate of energy density from remote-sensing observations. We use extreme-ultraviolet observations to infer the magnetic structure of the source active region NOAA 11745, and Nançay Radioheliograph imaging spectroscopy to estimate the speed and origin of the escaping electron beams. Using the observationally deduced electron-beam properties from the type III bursts and cotemporal hard X-rays, we simulate electron-beam properties to estimate the electron number density and energy in the acceleration region. We find an electron density (above 30 keV) in the acceleration region of 10^2.5 cm⁻³ and an energy density of 2 × 10⁻⁵ erg cm⁻³. Radio observations suggest the particles travelled a very short distance before they began to produce radio emission, implying a radially narrow acceleration region. A short but plausibly wide slab-like acceleration volume of 10²⁶–10²⁸ cm³ atop the flaring loop arcade could contain a total energy of 10²³–10²⁵ erg (∼100 beams), which is comparable to energy estimates from previous studies.

中文翻译：

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估计逃离加速太阳电子束的总能量含量


量化太阳爆发事件期间加速电子束的能量含量是一个关键的突出目标，必须对其进行限制，以改进粒子加速模型并了解太空天气的电子分量。以前的估计使用地球附近的原位测量，因此受到电子束传播效应的影响。在这项研究中，我们推导出了在 2013 年 5 月 22 日太阳耀斑期间加速并产生 III 型射电暴的快速逃逸电子束序列的特性，包括从遥感观测中对能量密度的首次估计。我们使用极紫外观测来推断源活动区域 NOAA 11745 的磁性结构，并使用 Nançay 放射日光仪成像光谱来估计逃逸电子束的速度和来源。利用从 III 型爆发和共时硬 X 射线中观测推断出的电子束特性，我们模拟电子束特性以估计加速区域中的电子数密度和能量。我们发现电子密度（高于 30 keV）在 10^{2.5 cm-3} 的加速区域和 2 × ^10-5 erg ^cm-3 的能量密度。射电观测表明，这些粒子在开始产生射电发射之前行进了很短的距离，这意味着有一个径向狭窄的加速区域。在喇叭形环形拱廊顶部，一个短但似乎很宽的板状加速度体积为 10^{26-10 28} cm³，可能包含 10^{23-10 25} erg（∼100 光束）的总能量，这与以前研究的能量估计相当。