发表机构
Advanced Heliophysics Inc.（先进日球物理公司）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过半解析模型链追踪年轻太阳的日冕物质抛射，发现其减速耗散能量驱动太阳高能粒子，对早期地球产生自熄灭的强迫，并可能为前生命合成提供氮源。
AI 中文摘要
在大约39亿年前（恒星年龄约0.6吉年），年轻太阳的磁活动远比今天活跃。它每年向更致密、磁化更强的太阳风发射约10^2次大型快速日冕物质抛射（CME）。我们通过半解析模型链追踪这些爆发到地球大气层的过程。我们发现，以v0~3–4×10^3 km/s发射的CME在减速过程中耗散约6×10^25焦耳的动能，该能量仅由其发射和最终速度决定。扩散激波加速将其中约10%的能量转化为太阳高能粒子（SEP），其沉积深度主要取决于谱断裂能量Eb。我们表明，更强的磁场将阿尔文面（磁场控制太阳风的区域）从约10–25太阳半径移动到约40–60太阳半径，因此CME激波传递的粒子通量是耀斑的十倍以上。由于该强迫由减速提供动力，它遵循测量的太阳风历史（质量损失率∝t^-2.3）并以约t^-3的速率下降。它在39亿年前比20亿年前强约50–100倍，是今天水平的数百倍。这种下降在太阳最暗时最强，这正是微弱年轻太阳（FYS）问题的温室解决方案通常人为施加的。其幅度很小：SEP驱动的N2O最多只能为20–40 W/m²的温室需求增加几W/m²，且仅当分形有机雾霾延长其寿命时才有效。计算沉积在约1 hPa以下存活水平的能量，我们发现这些粒子每年固定约4×10^10–4×10^11摩尔氮，这可能为地表水体提供前生命原料。最大的不确定性是Eb、事件发生率、存活深度和N2O寿命。
英文摘要
At $\sim$3.9~Ga (stellar age $\sim$0.6~Gyr), the young Sun was far more magnetically active than today. It launched $\sim$$10^2$ large, fast coronal mass ejections (CMEs) per year into a denser, more magnetized wind. We follow these eruptions to Earth's atmosphere with a semi-analytic model chain. We find that a CME launched at $v_0\sim3\text{--}4\e{3}\unit{km\,s^{-1}}$ dissipates $ΔE_k\sim6\e{25}\unit{J}$ as it decelerates, an amount set only by its launch and final speeds. Diffusive shock acceleration converts $\sim$10\% of this energy into solar energetic particles (SEPs), whose deposition depth depends mainly on a spectral break energy $E_b$. We show that the stronger field moves the Alfvén surface, inside which the magnetic field controls the wind, from $\sim$10--25$\,\Rsun$ to $\sim$40--60$\,\Rsun$, so CME shocks deliver over ten times the particle fluence of flares. Because the forcing is powered by deceleration, it follows the measured wind history ($\dot M\propto t^{-2.3}$) and declines as $\sim t^{-3}$. It was $\sim$50--100 times stronger at 3.9~Ga than at 2~Ga and several hundred times today's level. This decline, strongest when the Sun was faintest, is what greenhouse solutions of the faint young Sun (FYS) problem usually impose by hand. The magnitude is small: SEP-driven $\mathrm{N_2O}$ adds at most a few $\unit{W\,m^{-2}}$ to a 20--40$\unit{W\,m^{-2}}$ greenhouse requirement, and only if a fractal organic haze extends its lifetime. Counting energy deposited below a survival level near 1~hPa, we find the particles fix $\sim$$4\e{10}$--$4\e{11}\unit{mol\,N\,yr^{-1}}$, which could supply prebiotic feedstock to surface pools. The largest uncertainties are $E_b$, the event rate, the survival depth, and the $\mathrm{N_2O}$ lifetime.
Comments26 pages, 9 figures
