太阳光球磁场特征物理量在质子事件短期预报中的应用

利用SOHO/MDI全日面纵向磁图, 计算了三个描述太阳活动区磁场复杂性和非势性的特征物理量, 即纵向磁场最大水平梯度Bz, 强梯度中性线长度L, 孤立奇点数目η. 为检验太阳光球磁场特征在质子事件短期预报中是否有效, 采用BP神经网络方法, 建立了基于这三个磁场特征物理量简单的太阳质子事件短期(24h)预报模型. 模 型在对2002年和2003年连续两年的样本检测中, 有很高的准确率(2002年和2003年 分别为90 %, 87.54 %)和较高的 质子事件报准率(2002年和2003年分别为60 %, 75 %),从而为光球磁场特征物理量作为质子事件预报的有效因子提供了依据.

Application of Solar Photospheric Magnetic Field Properties in SPE Short-term Forecast

Solar Proton Events (SPE) are one kind of the major solar energy release phenomena.The released energies are well known from the magnetic energy. Lots of observations and studies have suggested that solar fiares and CME (Coronal Mass Eruptions) are closely correlated to the complexity and non-potentiality of solar magnetic fields. Applying SOHO/MDI full-disk photospheric magnetograms, three magnetic physical properties (the maximum horizontal gradient of longitudinal magnetic field |▽_hB_z|m, the length of neutral line with strong gradients L, the number of singular points η) are calculated, which describes the complexity and non-potentiality of solar magnetic fields.In order to verify that solar photospheric magnetic properties are available at forecasting SPE, a simple SPE forecast model that can forecast whether SPE will happen or not in the future 24 hours is set up, which is based on the three physical properties with BP (Back Propagation) neural network.In the consecutive tests for the 2002 and 2003 year samples,the model has very high accuracy rates (90％for 2002 and 87.54％for 2003,respectively)and the rather high SPE probabilities of detection (60％for 2002 and 75％for 2003,respectively),which supported that solar photospheric magnetic properties are very available in the SPE forecast models.