臺灣博碩士論文加值系統

中文摘要已經有許多科學家對於地球船頭震波(bow shock)有著相當程度
的研究.Fairfield[1971]是最早以雙曲線模型來對船頭震波的位置作最佳
擬合(best fit).以ISEE2和IMP8為主的資料,我們發現以拋物線模型會更
適合.這個拋物線模型r=r0[2/(1+cos(thi))]**(alpha).這個模型有兩個
變數r0與(alpha),(分別表示在日地直線上,地球至地球船頭震波的距離,
以及地球船頭震波的張角)與太陽風(solar wind)中的電漿(plasma)資料
Bz(z component of interplanetarymagnetic field),Mms(magnetosonic
Machnumber)和Dp(dynamic pressure)的關係.其最佳擬合的結果中,地球
船頭震波的位置會隨南向的IMF變大而變小,這是因為南向的IMF使得磁層
頂的位置改變了.r0會隨著Mms的增加而減少,(alpha)則反之.

abstractThe physics of the Earth's bow shock had beenstudied by
many scientists. Fairfield[1971]proposed a hyperbolic model to
best fit the Earth's bow shock position. We find that a
parabolic curve is more agreed with the shape of the bow shock
from observations of ISEE2 (International Sun-Earth Explorer2)
and IMP8.The parabloic model is described in the form r=r0[2/(1+
cos(thi))]**(alpha).The model has twoparameter r0 and (alpha),
representing respectively the standoff distance and the level of
flaring,which are varied with the z component of interplanetary
magnetic field (IMF)Bz, solar windMach number Mms and dynamic
pressure Dp. With thisrelation, we can predict the position and
shape ofthe bow shock for a given solar wind condition. The
best-fit results show that the size of the bow shock decreases
while the magnitude of southward IMFincreases. It is due to the
size of the magnetopause decreases by the southward IMF. The
value of r0 decreases when the Mach number Mms increase, but
vicecersa for the flaring (alpha).