The bipolar electric field solitary(EFS)structures observed frequently in space plasmas by satellites have two different polarities,first positive electric field peak then negative(i.e.,positive/negative)and first neg...The bipolar electric field solitary(EFS)structures observed frequently in space plasmas by satellites have two different polarities,first positive electric field peak then negative(i.e.,positive/negative)and first negative then positive peak(i.e.,negative/positive).We provide the physical explanation on the polarity of observed bipolar EFS structures with an electrostatic ion fluid model.The results show that if initial electric field𝐸E_(0)>0,the polarity of the bipolar EFS structure will be positive/negative;and if𝐸E_(0)<0,the polarity of the bipolar EFS structure will be negative/positive.However,for a fixed polarity of the EFS,either positive/negative or negative/positive,if the satellite is located at the positive side of the EFS,the observed polarity should be positive/negative,if the satellite is located at the negative side of the EFS,the observed polarity should be negative/positive.Therefore,we provide a method to clarify the natural polarity of the EFS with observed polarity by satellites.Our results are significant to understand the physical process in space plasma with the satellite observation.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 40874084,41074114 and 40921063the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KJCX2-YW-T13-3by the Project Supported by the Specialized Research Fund for State Key Laboratories.
文摘The bipolar electric field solitary(EFS)structures observed frequently in space plasmas by satellites have two different polarities,first positive electric field peak then negative(i.e.,positive/negative)and first negative then positive peak(i.e.,negative/positive).We provide the physical explanation on the polarity of observed bipolar EFS structures with an electrostatic ion fluid model.The results show that if initial electric field𝐸E_(0)>0,the polarity of the bipolar EFS structure will be positive/negative;and if𝐸E_(0)<0,the polarity of the bipolar EFS structure will be negative/positive.However,for a fixed polarity of the EFS,either positive/negative or negative/positive,if the satellite is located at the positive side of the EFS,the observed polarity should be positive/negative,if the satellite is located at the negative side of the EFS,the observed polarity should be negative/positive.Therefore,we provide a method to clarify the natural polarity of the EFS with observed polarity by satellites.Our results are significant to understand the physical process in space plasma with the satellite observation.
