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球坐标


SphericalCoordinates

球坐标,也称为球极坐标(Walton 1967, Arfken 1985),是一种曲线坐标系,自然用于描述球体椭球体上的位置。定义 thetaxy-平面内从 x开始的方位角,其中 0<=theta<2pi(当被称为经度时,记为 lambda),phi 为从正 z开始的极角(也称为天顶角余纬度,其中 phi=90 degrees-deltadelta纬度),其中 0<=phi<=pir 为从点到原点的距离(半径)。这是数学中常用的约定。

在这项工作中,遵循数学惯例,径向、方位角天顶角坐标的符号分别取为 rthetaphi。请注意,此定义提供了常用极坐标符号的逻辑扩展,其中 theta 仍然是 xy-平面内的,而 phi 成为该平面外的。在这项工作中,此约定的唯一例外是在球谐函数中,其中保留了物理文献中使用的约定(希望这比愚蠢的严格一致性可能产生的混乱要少一些)。

不幸的是,符号 thetaphi 的含义和列出顺序都相反的约定也很常用,尤其是在物理学中。这尤其令人困惑,因为相同的符号 (r,theta,phi) 通常对数学家来说意味着(径向,方位角,极角),但对物理学家来说意味着(径向,极角,方位角)。符号 rho 有时也用于代替 rtheta 代替 theta,以及 phipsi 代替 phi。下表总结了不同作者使用的一些约定。因此,查阅文献时需要格外小心。

顺序符号参考
(径向,方位角,极角)(r,theta,phi)本工作
(径向,方位角,极角)(rho,theta,phi)Apostol (1969, p. 95), Anton (1984, p. 859), Beyer (1987, p. 212)
(径向,极角,方位角)(r,theta,phi)SphericalPlot3DWolfram 语言
(径向,极角,方位角)(r,theta,phi)ISO 31-11, Misner et al. (1973, p. 205)
(径向,极角,方位角)(r,theta,phi)Arfken (1985, p. 102)
(径向,极角,方位角)(r,theta,psi)Moon and Spencer (1988, p. 24)
(径向,极角,方位角)(r,theta,phi)Korn and Korn (1968, p. 60), Bronshtein et al. (2004, pp. 209-210)
(径向,极角,方位角)(rho,phi,theta)Zwillinger (1996, pp. 297-299)

球坐标 (r,theta,phi)笛卡尔坐标 (x,y,z) 的关系为

r=sqrt(x^2+y^2+z^2)
(1)
theta=tan^(-1)(y/x)
(2)
phi=cos^(-1)(z/r),
(3)

其中 r in [0,infty)theta in [0,2pi),以及 phi in [0,pi],并且必须适当定义反正切以考虑 (x,y) 的正确象限。

笛卡尔坐标表示,

x=rcosthetasinphi
(4)
y=rsinthetasinphi
(5)
z=rcosphi.
(6)

比例因子为

h_r=1
(7)
h_theta=rsinphi
(8)
h_phi=r,
(9)

因此,度量系数为

g_(rr)=1
(10)
g_(thetatheta)=r^2sin^2phi
(11)
g_(phiphi)=r^2.
(12)

线元素为

 ds=drr^^+rdphiphi^^+rsinphidthetatheta^^,
(13)

面积元素

 da=r^2sinphidthetadphi,
(14)

和体积元素

 dV=r^2sinphidphidthetadr.
(15)

雅可比行列式为

 |(partial(x,y,z))/(partial(r,theta,phi))|=r^2sinphi.
(16)

径向向量为

 r=[rcosthetasinphi; rsinthetasinphi; rcosphi],
(17)

因此,单位向量为

r^^=((dr)/(dr))/(|(dr)/(dr)|)
(18)
=[costhetasinphi; sinthetasinphi; cosphi]
(19)
theta^^=((dr)/(dtheta))/(|(dr)/(dtheta)|)
(20)
=[-sintheta; costheta; 0]
(21)
phi^^=((dr)/(dphi))/(|(dr)/(dphi)|)
(22)
=[costhetacosphi; sinthetacosphi; -sinphi].
(23)

单位向量的导数为

(partialr^^)/(partialr)=0
(24)
(partialtheta^^)/(partialr)=0
(25)
(partialphi^^)/(partialr)=0
(26)
(partialr^^)/(partialtheta)=sinphitheta^^
(27)
(partialtheta^^)/(partialtheta)=-cosphiphi^^-sinphir^^
(28)
(partialphi^^)/(partialtheta)=cosphitheta^^
(29)
(partialr^^)/(partialphi)=phi^^
(30)
(partialtheta^^)/(partialphi)=0
(31)
(partialphi^^)/(partialphi)=-r^^.
(32)

梯度为

 del =r^^partial/(partialr)+1/rphi^^partial/(partialphi)+1/(rsinphi)theta^^partial/(partialtheta),
(33)

及其分量为

del _rr^^=0
(34)
del _thetar^^=1/rtheta^^
(35)
del _phir^^=1/rphi^^
(36)
del _rtheta^^=0
(37)
del _thetatheta^^=-(cotphi)/rphi^^-1/rr^^
(38)
del _phitheta^^=0
(39)
del _rphi^^=0
(40)
del _thetaphi^^=1/rcotphitheta^^
(41)
del _phiphi^^=-1/rr^^
(42)

(Misner et al. 1973, p. 213,但他们使用符号约定 (r,phi,theta))。

Misner et al. (1973, p. 209) 定义的第二类克里斯托费尔符号由下式给出

Gamma^r=[0 0 0; 0 -1/r 0; 0 0 -1/r]
(43)
Gamma^theta=[0 1/r 0; 0 0 0; 0 (cotphi)/r 0]
(44)
Gamma^phi=[0 0 1/r; 0 -(cotphi)/r 0; 0 0 0]
(45)

(Misner et al. 1973, p. 213,但他们使用符号约定 (r,phi,theta))。Arfken (1985) 定义的第二类克里斯托费尔符号由下式给出

Gamma^r=[0 0 0; 0 -rsin^2phi 0; 0 0 -r]
(46)
Gamma^theta=[0 1/r 0; 1/r 0 cotphi; 0 cotphi 0]
(47)
Gamma^phi=[0 0 1/r; 0 -sinphicosphi 0; 1/r 0 0]
(48)

(Walton 1967;Moon and Spencer 1988, p. 25a;但他们都使用符号约定 (r,phi,theta))。

散度为

 del ·F=partial/(partialr)A^r+2/rA^r+1/(rsinphi)partial/(partialtheta)A^theta+1/rpartial/(partialphi)A^phi+(cotphi)/rA^phi,
(49)

或者,用向量表示法,

del ·F=(2/r+partial/(partialr))F_r+(1/rpartial/(partialphi)+(cotphi)/r)F_phi+1/(rsinphi)(partialF_theta)/(partialtheta)
(50)
=1/(r^2)partial/(partialr)(r^2F_r)+1/(rsinphi)partial/(partialphi)(sinphiF_phi)+1/(rsinphi)(partialF_theta)/(partialtheta).
(51)

协变导数由下式给出

 A_(j;k)=1/(g_(kk))(partialA_j)/(partialx_k)-Gamma_(jk)^iA_i,
(52)

因此

A_(r;r)=(partialA_r)/(partialr)
(53)
A_(r;theta)=1/(rsinphi)(partialA_r)/(partialphi)-(A_theta)/r
(54)
A_(r;phi)=1/r((partialA_r)/(partialphi)-A_phi)
(55)
A_(theta;r)=(partialA_theta)/(partialr)
(56)
A_(theta;theta)=1/(rsinphi)(partialA_theta)/(partialtheta)+(cotphi)/rA_phi+(A_r)/r
(57)
A_(theta;phi)=1/r(partialA_theta)/(partialr)-Gamma_(phir)^iA_i(partialA_theta)/(partialphi)
(58)
A_(phi;r)=(partialA_phi)/(partialr)-Gamma_(phir)^iA_i=(partialA_phi)/r
(59)
A_(phi;theta)=1/(rsinphi)(partialA_phi)/(partialtheta)-(cotphi)/rA_theta
(60)
A_(phi;phi)=1/r(partialA_phi)/(partialphi)+(A_r)/r.
(61)

对易系数由下式给出

 c_(alphabeta)^mue^->_mu=[e^->_alpha,e^->_beta]=del _alphae^->_beta-del _betae^->_alpha
(62)
 [r^^,r^^]=[theta^^,theta^^]=[phi^^,phi^^]=0,
(63)

因此 c_(rr)^alpha=c_(thetatheta)^alpha=c_(phiphi)^alpha=0,其中 alpha=r,theta,phi

 [r^^,theta^^]=-[theta^^,r^^]=del _rtheta^^-del _thetar^^=0-1/rtheta^^=-1/rtheta^^,
(64)

因此 c_(rtheta)^theta=-c_(thetar)^theta=-1/rc_(rtheta)^r=c_(rtheta)^phi=0

 [r^^,phi^^]=-[phi^^,r^^]=0-1/rphi^^=-1/rphi^^,
(65)

因此 c_(rphi)^phi=-c_(phir)^phi=1/r

 [theta^^,phi^^]=-[phi^^,theta^^]=1/rcotphitheta^^-0=1/rcotphitheta^^,
(66)

因此

 c_(thetaphi)^theta=-c_(phitheta)^theta=1/rcotphi.
(67)

总结,

c^r=[0 0 0; 0 0 0; 0 0 0]
(68)
c^theta=[0 -1/r 0; 1/r 0 1/rcotphi; 0 -1/rcotphi 0]
(69)
c^phi=[0 0 -1/r; 0 0 0; 1/r 0 0].
(70)

径向向量的时间导数为

r^.=[costhetasinphir^.-rsinthetasinphitheta^.+rcosthetacosphiphi^.; sinthetasinphir^.+rcosthetasinphitheta^.+rsinthetacosphiphi^.; cosphir^.-rsinphiphi^.]
(71)
=[costhetasinphi; sinthetasinphi; cosphi]r^.+rsinphi[-sintheta; costheta; 0]theta^.+r[costhetacosphi; sinthetacosphi; -sinphi]phi^.
(72)
=r^.r^^+rsinphitheta^.theta^^+rphi^.phi^^.
(73)

因此,速度由下式给出

 v=|r^.|=sqrt(r^.^2+r^2sin^2phitheta^.^2+r^2phi^.^2).
(74)

加速度为

x^..=(-sinthetasinphitheta^.r^.+costhetacosphir^.phi^.+costhetasinphir^..)-(sinthetasinphir^.theta^.+rcosthetasinphitheta^.^2+rsinthetacosphitheta^.phi^.+rsinthetasinphitheta^..)+(costhetacosphir^.phi^.-rsinthetacostheta^.phi^.-rcosthetasinphiphi^.^2+rcosthetacosphiphi^..)
(75)
=-2sinthetasinphitheta^.r^.+2costhetacosphir^.phi^.-2rsinthetacosphitheta^.phi^.+costhetasinphir^..-rsinthetasinphitheta^..+rcosthetacosphiphi^..-rcosthetasinphi(theta^.^2+phi^.^2)
(76)
y^..=(sinthetasinphir^..+rcosthetasinphitheta^.+rcosphisinthetaphi^.)+(costhetasinphir^.theta^.-rsinthetasinphitheta^.^2+rcosthetacosphitheta^.phi^.+rcosthetasinphitheta^..)+(sinthetacosphir^.phi^.+rcosthetacosphitheta^.phi^.-rsinthetasinphiphi^.^2+rsinthetacosphiphi^..)
(77)
=2costhetasinphitheta^.r^.+2sinthetacosphir^.phi^.+2rcosthetacosphitheta^.phi^.+sinthetasinphir^..+rcosthetasinphitheta^..+rsinthetacosphiphi^..-rsinthetasinphi(theta^.^2+phi^.^2)
(78)
z^..=(cosphir^..-sinphir^.phi^.)-(r^.sinphiphi^.+rcosphiphi^.^2+rsinphiphi^..)
(79)
=-rcosphiphi^.^2+cosphir^..-2sinphiphi^.r^.-rsinphiphi^...
(80)

将这些代入得到

r^..=(r^..-rphi^.^2)[costhetasinphi; sinthetasinphi; cosphi]+(2rcosphitheta^.phi^.+2sinphitheta^.r^.+rsinphitheta^..)[-sintheta; costheta; 0]+(2r^.phi^.+rphi^..)[costhetacosphi; sinthetacosphi; -sinphi]-rsinphitheta^.^2[costheta; sintheta; 0],
(81)

但是

sinphir^^+cosphiphi^^=[costhetasin^2phi+costhetacos^2phi; sinthetasin^2phi+sinthetacos^2phi; 0]
(82)
=[costheta; sintheta; 0],
(83)

因此

r^..=(r^..-rphi^.^2)r^^+(2rcosphitheta^.phi^.+2sinphitheta^.r^.+rsinphitheta^..)theta^^+(2r^.phi^.+rphi^..)phi^^-rsinphitheta^.^2(sinphir^^+cosphiphi^^)
(84)
=(r^..-rphi^.^2-rsin^2phitheta^.^2)r^^+(2sinphitheta^.r^.+2rcosphitheta^.phi^.+rsinphitheta^..)theta^^+(2r^.phi^.+rphi^..-rsinphicosphitheta^.^2)phi^^.
(85)

单位向量的时间导数为

r^^^.=sinphitheta^.theta^^+phi^.phi^^
(86)
theta^^^.=-theta^.(sinphir^^+cosphiphi^^)
(87)
phi^^^.=-phi^.r^^+cosphitheta^.theta^^.
(88)

旋度为

 del ×F=1/(rsinphi)[partial/(partialphi)(sinphiF_theta)-(partialF_phi)/(partialtheta)]r^^+1/r[1/(sinphi)(partialF_r)/(partialtheta)-partial/(partialr)(rF_theta)]phi^^+1/r[partial/(partialr)(rF_phi)-(partialF_r)/(partialphi)]theta^^.
(89)

拉普拉斯算子为

del ^2=1/(r^2)partial/(partialr)(r^2partial/(partialr))+1/(r^2sin^2phi)(partial^2)/(partialtheta^2)+1/(r^2sinphi)partial/(partialphi)(sinphipartial/(partialphi))
(90)
=1/(r^2)(r^2(partial^2)/(partialr^2)+2rpartial/(partialr))+1/(r^2sin^2phi)(partial^2)/(partialtheta^2)+1/(r^2sinphi)(cosphipartial/(partialphi)+sinphi(partial^2)/(partialphi^2))
(91)
=(partial^2)/(partialr^2)+2/rpartial/(partialr)+1/(r^2sin^2phi)(partial^2)/(partialtheta^2)+(cosphi)/(r^2sinphi)partial/(partialphi)+1/(r^2)(partial^2)/(partialphi^2).
(92)

球坐标中的向量拉普拉斯算子由下式给出

 del ^2v=[1/r(partial^2(rv_r))/(partialr^2)+1/(r^2)(partial^2v_r)/(partialtheta^2)+1/(r^2sin^2theta)(partial^2v_r)/(partialphi^2)+(cottheta)/(r^2)(partialv_r)/(partialtheta)-2/(r^2)(partialv_theta)/(partialtheta)-2/(r^2sintheta)(partialv_phi)/(partialphi)-(2v_r)/(r^2)-(2cottheta)/(r^2)v_theta 
1/r(partial^2(rv_(theta)))/(partialr^2)+1/(r^2)(partial^2v_(theta))/(partialtheta^2)+1/(r^2sin^2theta)(partial^2v_(theta))/(partialphi^2)+(cottheta)/(r^2)(partialv_(theta))/(partialtheta)-2/(r^2)(cottheta)/(sintheta)(partialv_(phi))/(partialphi)+2/(r^2)(partialv_r)/(partialtheta)-(v_(theta))/(r^2sin^2theta) 
1/r(partial^2(rv_(phi)))/(partialr^2)+1/(r^2)(partial^2v_(phi))/(partialtheta^2)+1/(r^2sin^2theta)(partial^2v_(phi))/(partialphi^2)+(cottheta)/(r^2)(partialv_(phi))/(partialtheta)+2/(r^2sintheta)(partialv_r)/(partialphi)+(2cottheta)/(r^2sintheta)(partialv_(theta))/(partialphi)-(v_(phi))/(r^2sin^2theta) ].
(93)

为了用球坐标的偏导数表示关于笛卡尔轴的偏导数,

[x; y; z]=[rcosthetasinphi; rsinthetasinphi; rcosphi]
(94)
[dx; dy; dz]=[costhetasinphidr-rsinthetasinphidtheta+rcosthetacosphidphi; sinthetasinphidr+rsinphicosthetadtheta+rsinthetacosphidphi; cosphidr-rsinphidphi]
(95)
=[costhetasinphi -rsinthetasinphi rcosthetacosphi; sinthetasinphi rcosthetasinphi rsinthetacosphi; cosphi 0 -rsinphi][dr; dtheta; dphi].
(96)

反演后,结果是

 [dr; dtheta; dphi]=[costhetasinphi sinthetasinphi cosphi; -(sintheta)/(rsinphi) (costheta)/(rsinphi) 0; (costhetacosphi)/r (sinthetacosphi)/r -(sinphi)/r][dx; dy; dz].
(97)

因此,球坐标中的笛卡尔偏导数为

partial/(partialx)=costhetasinphipartial/(partialr)-(sintheta)/(rsinphi)partial/(partialtheta)+(costhetacosphi)/rpartial/(partialphi)
(98)
partial/(partialy)=sinthetasinphipartial/(partialr)+(costheta)/(rsinphi)partial/(partialtheta)+(sinthetacosphi)/rpartial/(partialphi)
(99)
partial/(partialz)=cosphipartial/(partialr)-(sinphi)/rpartial/(partialphi)
(100)

(Gasiorowicz 1974, pp. 167-168; Arfken 1985, p. 108)。

亥姆霍兹微分方程在球坐标中是可分离的。


另请参阅

方位角, 余纬度, 大圆, 亥姆霍兹微分方程--球坐标, 纬度, 经度, 扁球面坐标, 极角, 极坐标, 极坐标图, 极向量, 长球面坐标, 天顶角 在 MathWorld 课堂中探索此主题

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参考资料

Anton, H. Calculus with Analytic Geometry, 2nd ed. New York: Wiley, 1984.Apostol, T. M. Calculus, 2nd ed., Vol. 2: Multi-Variable Calculus and Linear Algebra, with Applications to Differential Equations and Probability. Waltham, MA: Blaisdell, 1969.Arfken, G. "Spherical Polar Coordinates." §2.5 in Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, pp. 102-111, 1985.Beyer, W. H. CRC Standard Mathematical Tables, 28th ed. Boca Raton, FL: CRC Press, 1987.Bronshtein, I. N.; Semendyayev, K. A.; Musiol, G.; and Muehlig, H. Handbook of Mathematics, 4th ed. New York: Springer-Verlag, 2004.Gasiorowicz, S. Quantum Physics. New York: Wiley, 1974.Korn, G. A. and Korn, T. M. Mathematical Handbook for Scientists and Engineers. New York: McGraw-Hill, 1968.Misner, C. W.; Thorne, K. S.; and Wheeler, J. A. Gravitation. San Francisco, CA: W. H. Freeman, 1973.Moon, P. and Spencer, D. E. "Spherical Coordinates (r,theta,psi)." Table 1.05 in Field Theory Handbook, Including Coordinate Systems, Differential Equations, and Their Solutions, 2nd ed. New York: Springer-Verlag, pp. 24-27, 1988.Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, p. 658, 1953.Walton, J. J. "Tensor Calculations on Computer: Appendix." Comm. ACM 10, 183-186, 1967.Zwillinger, D. (Ed.). "Spherical Coordinates in Space." §4.9.3 in CRC Standard Mathematical Tables and Formulae. Boca Raton, FL: CRC Press, pp. 297-298, 1995.

在 Wolfram|Alpha 上引用

球坐标

引用为

Weisstein, Eric W. "球坐标。" 来自 MathWorld--Wolfram Web 资源。 https://mathworld.net.cn/SphericalCoordinates.html

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