标题： 太阳耀斑日冕中由于共空间回流电流损耗导致的非热电子向下能流的减少 显示英文标题

标题： Reduction of the downward energy flux of non-thermal electrons in the solar flare corona due to co-spatial return current losses

摘要： 高能电子携带了太阳耀斑的大部分能量。 因此，理解电子束分布的变化对于它们的传播至关重要。 本文的重点之一是如何通过共空间回流电流减少这些加速电子的能量通量。 我们系统地计算了各种与太阳耀斑相关的束流和等离子体参数下的这种减少。 我们的1维模型考虑了束流电子与等离子体电子之间的碰撞、回流电流电场减速、温热靶近似中的热化以及逃逸电子的贡献。 结果集中在经典的（斯庇策）范围内，提供了能量通量减少及其程度的一个有价值的基准。 回流电流损失仅在最低非热通量的情况下可以忽略不计。 我们计算了回流电流损失变得显著的条件，并估计了束流能量通量密度变化的程度。 我们也计算了两个在更高注入通量下发生的额外条件：（1）逃逸电子变得显著的情况，以及（2）电流驱动不稳定性可能变得显著的情况，这需要一个能够自洽处理这些现象的模型。 条件（2）在存在逃逸电子的情况下得到缓解，能量通量损失也相应减少。 所有结果都依赖于束流和共空间等离子体参数。 我们还考察了束流电子被回流电流电场反射的重要性。 我们表明，需要重新审视一些耀斑的解释，以考虑回流电流的影响。 显示英文摘要

摘要： High energy electrons carry much of a solar flare's energy. Therefore, understanding changes in electron beam distributions during their propagation is crucial. A key focus of this paper is how the co-spatial return current reduces the energy flux carried by these accelerated electrons. We systematically compute this reduction for various beam and plasma parameters relevant to solar flares. Our 1D model accounts for collisions between beam and plasma electrons, return current electric-field deceleration, thermalization in a warm target approximation, and runaway electron contributions. The results focus on the classical (Spitzer) regime, offering a valuable benchmark for energy flux reduction and its extent. Return current losses are only negligible for the lowest nonthermal fluxes. We calculate the conditions for return current losses to become significant and estimate the extent of the modification to the beam's energy flux density. We also calculate two additional conditions which occur for higher injected fluxes: (1) where runaway electrons become significant, and (2) where current-driven instabilities might become significant, requiring a model that self-consistently accounts for them. Condition (2) is relaxed and the energy flux losses are reduced in the presence of runaway electrons. All results are dependent on beam and co-spatial plasma parameters. We also examine the importance of the reflection of beam electrons by the return-current electric field. We show that the interpretation of a number of flares needs to be reviewed to account for the effects of return currents.