In this study, we suggest a new method to estimate the mass of a halo coronal mass ejection (CME) using synthetic CMEs. For this, we generate synthetic CMEs based on two assumptions: (1) the CME structure is a full ice cream cone, and (2) the CME electron number density follows a power-law distribution (ρ _cme=ρ ₀ r ⁻ⁿ ). The power-law exponent n is obtained by minimizing the rms error between the electron number density distributions of an observed CME and the corresponding synthetic CME at a position angle of the CME leading edge. By applying this methodology to 56 halo CMEs, we estimate two kinds of synthetic CME masses. One is a synthetic CME mass that considers only the observed CME region (M _cme1), the other is a synthetic CME mass that includes both the observed CME region and the occulted area (M _cme2). From these two cases, we derive conversion factors that are the ratio of a synthetic CME mass to an observed CME mass. The conversion factor for M _cme1 ranges from 1.4 to 3.0 and its average is 2.0. For M _cme2, the factor ranges from 1.8 to 5.0 with an average of 3.0. These results imply that the observed halo CME mass can be underestimated by about 2 times when we consider the observed CME region, and about 3 times when we consider the region including the occulted area. Interestingly these conversion factors have a very strong negative correlation with angular widths of halo CMEs.

在这项研究中，我们建议了一种使用合成CME估算晕轮冠物质抛射（CME）质量的新方法。为此，我们生成基于两个假设合成的CME：（1）CME结构是一个完整的冰淇淋锥体，和（2）的CME电子数密度遵循幂律分布（ρ _CME = ρ ₀ [R ^{- Ñ} ） 。幂律指数n是通过使CME前沿的位置角处观察到的CME和相应的合成CME的电子数密度分布之间的均方根误差最小而获得的。通过将此方法应用于56个晕波CME，我们估计了两种合成CME的质量。一种是合成的CME质量，它仅考虑观察到的CME区域（M _cme1），另一个是合成的CME质量，既包含观察到的CME区域又包含_隐匿区域（M _cme2）。从这两种情况，我们得出转换因子，即合成CME质量与观察到的CME质量之比。M _cme1的转换因子范围为1.4到3.0，平均值为2.0。对于M _cme2，该因子范围从1.8到5.0，平均为3.0。这些结果表明，当我们考虑所观察到的CME区域时，所观察到的CME晕圈质量可能被低估了大约2倍，而当考虑到包括隐蔽区域在内的区域时，被低估了大约3倍。有趣的是，这些转换因子与光晕CME的角宽度具有非常强的负相关性。