【摘要】 我们指出,对数耀斑指数 F_L=Log[0.76/T^* ∑A_d²]保持着明确的物理含意:对应于耀斑辐射积分强度的量级。单个耀斑面积A_d以10^-6太阳圆面面积为单位量度;T^*是有效观测时间（单位:分）。F₁具有优良的统计性能,遵从正态分布;从而,其时段平均值（?）_L和标准差σ,便可完备地统计描写该时段的耀斑活动水平。在中等时间尺度上（10—100天）,（?）_L与2800兆赫太阳流量（?）_a相关演变。短波衰退（SWF）强度指数(（?）_w,σ_sw)及其频数(（?）_sw,σ_fsw)与（?）_L的相关系数,均高于与黑子相对数（?）_z或太阳流量（?）_a的相关系数;线性相关置信水平大于99.9%。看来,对数耀斑指数F_L是更为有效的太阳活动指数。更多还原

【Abstract】 In this paper, it is pointed out that the Logarithmic Flare IndexF₁=Log（0.76/T^*ΣA_d²）has a clear physical meaning: it corresponds to the order of magnitude of the integral radiant intensity of flares. Here, individual flare areas A_d are measured in millionths of solar disk and T^* is lhe effective observing time in miuntes.A normal distribution holds for the Logarithmic Flare Index and so it possesses good statistical properties; consequently, its mean value ■ and its standard deviation σ_F in any period of time can be used completely to statistically describe the level of flare activity in that period.In a time interval of 10 to 100 days, the Logarithmic Flarc Index is correlated with the solar flux（■_a, σ_s） at 2800 MH; the correlation coefficients of the strenth index (■_w, σ_sw) and the daily incidence(■_sw, σ_fsw) of the Short Wave Fade-out with ■ are notably higher than the correlation coefficients with the Relative Sunspot Numbers ■_z and the solar flux ■_a。It appears that the Logarithmic Flare Index is an even more effective index of solar activity。更多还原