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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.
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 demonstrated 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 hemispheresDifferent.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 increa sing 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.