太阳风向磁层-电离层(Magnetosphere and Ionosphere,MI)系统输入能量,而输入的能量随后在MI系统中消耗.本文从能量守恒原理出发,讨论太阳风-磁层-电离层(SMI)耦合过程中的能流路径和能量收支的定量关系.主要讨论9个问题:(1)太阳风向MI...太阳风向磁层-电离层(Magnetosphere and Ionosphere,MI)系统输入能量,而输入的能量随后在MI系统中消耗.本文从能量守恒原理出发,讨论太阳风-磁层-电离层(SMI)耦合过程中的能流路径和能量收支的定量关系.主要讨论9个问题:(1)太阳风向MI系统的能量输入,(2)MI系统对能量输入的响应,(3)环电流的能量消耗,(4)极区电离层焦耳加热的能量消耗,(5)极光粒子沉降的能量消耗,(6)磁尾能量的消耗、储存以及返回下游太阳风,(7)平静期间的能量积累与释放,(8)能量在不同能汇中的分配,(9)评价能量函数的准则和方法.展开更多
The energy budget of the magnetosphere-ionosphere (MI) system during 1998-2008 was examined by using Akasofu's epsilon function. The results showed that 1) the yearly average rate of solar wind energy input into t...The energy budget of the magnetosphere-ionosphere (MI) system during 1998-2008 was examined by using Akasofu's epsilon function. The results showed that 1) the yearly average rate of solar wind energy input into the MI system was 4.51 GGJ (GGJ=1018 J), while the yearly average total dissipation was 4.30 GGJ; 2) the energy partitioning in the ring current and polar region was 56%:44%; 3) the energy input and dissipation processes continuously proceeded both in storm-substorm events and less disturbed intervals, suggesting the significant contribution of slow but long-lasting energy process during the less disturbance periods to the total energy budget. In addition, we found in this study an interesting phenomenon "self-adjustment ability" of the MI system which behaves just like a water reservoir. During solar active years, the input energy is more than the dissipated energy, implying that a portion of the input energy is not immediately released, but is stored in the magnetosphere. On the other hand, during less active years, the dissipated energy is more than the input energy, implying that the previously stored energy makes up for the energy input shortage in this period.展开更多
Although much has been done on the hemispheric asymmetry (or seasonal variations) of auroral hemispheric power (HP), the dependence of HP hemispheric asymmetry on solar cycle has not yet been studied. We have analyzed...Although much has been done on the hemispheric asymmetry (or seasonal variations) of auroral hemispheric power (HP), the dependence of HP hemispheric asymmetry on solar cycle has not yet been studied. We have analyzed data during 1979-2010 and investigated the dependence of HP hemispheric asymmetry/seasonal variation for the whole solar cycle. Here we show that (1) the hemispheric asymmetry of HP is positively correlated to the value of solar F10.7 with some time delay; (2) it is closely related to the coupling function between the solar wind and magnetosphere; and (3) the winter hemisphere receives more auroral power than the summer hemisphere for Kp ~0 to 6. The statistic results can be partly understood in the framework of the ionospheric conductivity feedback model. The similarity and differences between our results and previous results are discussed in the paper.展开更多
The dipole tilt angle has beenfound to affect Earth's bow shock.This work presents a quantitative relationship between the dipole tilt angle and the bow shock location and flaring angle.We collected a large data s...The dipole tilt angle has beenfound to affect Earth's bow shock.This work presents a quantitative relationship between the dipole tilt angle and the bow shock location and flaring angle.We collected a large data set of bow shock crossings from four different satellites(IMP 8,Geotail,Magion 4,and Cluster),including some recent crossings obtained during 2012-2013.The results from a statistical analysis demonstrate that:(1)the subsolar standoff distance increases but the flaring angle decreases with increasing dipole tilt angle;(2)when the dipole tilt angle changes sign from negative to positive,the dayside bow shock moves toward Earth and the shift can be as much as 2.29 R_E,during which the flaring angle increases;and(3)the shape of bow shock in the northern and southern hemispheres differs.For the northern hemisphere bow shock,with increasing positive/negative dipole tilt angle,the flaring angle increases/decreases.While for the southern hemisphere,the trend is the opposite;with increasing positive/negative dipole tilt angle,the flaring angle decreases/increases.These results are helpful for future bow shock modeling that needs to include the effects of dipole tilt angle.展开更多
文摘太阳风向磁层-电离层(Magnetosphere and Ionosphere,MI)系统输入能量,而输入的能量随后在MI系统中消耗.本文从能量守恒原理出发,讨论太阳风-磁层-电离层(SMI)耦合过程中的能流路径和能量收支的定量关系.主要讨论9个问题:(1)太阳风向MI系统的能量输入,(2)MI系统对能量输入的响应,(3)环电流的能量消耗,(4)极区电离层焦耳加热的能量消耗,(5)极光粒子沉降的能量消耗,(6)磁尾能量的消耗、储存以及返回下游太阳风,(7)平静期间的能量积累与释放,(8)能量在不同能汇中的分配,(9)评价能量函数的准则和方法.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40931056, 40874089)the National Basic Research Program of China ("973" Project) (Grant Nos. 2008CB425704)
文摘The energy budget of the magnetosphere-ionosphere (MI) system during 1998-2008 was examined by using Akasofu's epsilon function. The results showed that 1) the yearly average rate of solar wind energy input into the MI system was 4.51 GGJ (GGJ=1018 J), while the yearly average total dissipation was 4.30 GGJ; 2) the energy partitioning in the ring current and polar region was 56%:44%; 3) the energy input and dissipation processes continuously proceeded both in storm-substorm events and less disturbed intervals, suggesting the significant contribution of slow but long-lasting energy process during the less disturbance periods to the total energy budget. In addition, we found in this study an interesting phenomenon "self-adjustment ability" of the MI system which behaves just like a water reservoir. During solar active years, the input energy is more than the dissipated energy, implying that a portion of the input energy is not immediately released, but is stored in the magnetosphere. On the other hand, during less active years, the dissipated energy is more than the input energy, implying that the previously stored energy makes up for the energy input shortage in this period.
基金supported by Ocean Public Welfare Scientific Research Project, State Oceanic Administration People’s Republic of China (201005017)the National Basic Research Program of China(2011CB811404)
文摘Although much has been done on the hemispheric asymmetry (or seasonal variations) of auroral hemispheric power (HP), the dependence of HP hemispheric asymmetry on solar cycle has not yet been studied. We have analyzed data during 1979-2010 and investigated the dependence of HP hemispheric asymmetry/seasonal variation for the whole solar cycle. Here we show that (1) the hemispheric asymmetry of HP is positively correlated to the value of solar F10.7 with some time delay; (2) it is closely related to the coupling function between the solar wind and magnetosphere; and (3) the winter hemisphere receives more auroral power than the summer hemisphere for Kp ~0 to 6. The statistic results can be partly understood in the framework of the ionospheric conductivity feedback model. The similarity and differences between our results and previous results are discussed in the paper.
基金supported by the National Basic Research Program of China (Grant No.2012CB825606)the National Natural Science Foundation of China(Grant Nos.41574158,U1631107)the China Meteorological Administration(Grant No.GYHY201106011)
文摘The dipole tilt angle has beenfound to affect Earth's bow shock.This work presents a quantitative relationship between the dipole tilt angle and the bow shock location and flaring angle.We collected a large data set of bow shock crossings from four different satellites(IMP 8,Geotail,Magion 4,and Cluster),including some recent crossings obtained during 2012-2013.The results from a statistical analysis demonstrate that:(1)the subsolar standoff distance increases but the flaring angle decreases with increasing dipole tilt angle;(2)when the dipole tilt angle changes sign from negative to positive,the dayside bow shock moves toward Earth and the shift can be as much as 2.29 R_E,during which the flaring angle increases;and(3)the shape of bow shock in the northern and southern hemispheres differs.For the northern hemisphere bow shock,with increasing positive/negative dipole tilt angle,the flaring angle increases/decreases.While for the southern hemisphere,the trend is the opposite;with increasing positive/negative dipole tilt angle,the flaring angle decreases/increases.These results are helpful for future bow shock modeling that needs to include the effects of dipole tilt angle.
