3
a0 a1
F a2a4a3a4a22a8a23a24a5a4a6a16a7a11a9a11a25 7
F a26 10{11 a27 (a28a30a29 J (z) a31 N (z) a32a30a33a30a34 )
a35a24a36
a7a24a37a8a38a8a39a41a40a16a42a44a43a13a5a11a6
?
Etc `? `f `
??1:
?
Etc `? `f `
?
|HelmholtzZ??US"/s ?M
H;ü¤?è±sZ?
1
r
d
dr
?
rdR(r)dr
?
+
h
k2 ??? ?r2
i
R(r) = 0:
?Tk2 ?? 6= 0TMDx = pk2 ??r; y(x) = R(r)5Z?M1(Ӭ)BesselZ?
1
x
d
dx
?
xdy(x)dx
?
+
?
1? ”
2
x2
?
y(x) = 0;
?? = ”2
BesselZ?μ
??x = 0?x = 1 x = 0
^?5?x = 1
^d?5
?
?5?x = 0)·S‰ = §”
?
Bc?Xüp
BesselZ?x = 0?¥?53
/
?211
?
B/Xü¤?¥2T
?” 6=?
?
HBesselZ?¥
?(L?í1)?53
^
J§”(x) =
1X
k=0
(?)k
k!Γ(k§” +1)
?x
2
·2k§”
:
?T” =?
?n5Jn(x)?J?n(x)L?M1
J?n(x) = (?)nJn(x);
?
HBesselZ?¥?B3ˉ
^Jn(x)?=35 V|1
Nn(x) = 2…Jn(x)ln x2 ? 1…
n?1X
k=0
(n?k?1)!
k!
?x
2
·2k?n
?1…
1X
k=0
(?)k
k!(k +n)!
£?(n+k +1)+?(k +1)??x
2
·2k+n
;
iO???n = 0
H3??Vr
T??=[¥μK?
x17.1 Besself
?¥'?é?2:
x17.1 Besself
?¥'?é
BesselZ??¥”2'?Yè
^?'?′ù5
'00 +?' = 0;
'(0) = '(2…); '0(0) = '0(2…)
%?¥? = m2; m = 0;1;2;¢¢¢
yN'??|"×o
?
?¨Besself
?¥?é/
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[-Xü¤?V¥Bt2
T(m17.1?ó
-+?Besself
?¥m?)
m17.1 `Besself
?
1. J?n(x)?Jn(x)L?M1
J?n(x) = (?)nJn(x):
£
ün6.4?
2. Jn(x)¥}?
Jn(?x) = (?)nJn(x):
V[V” = n
H¥Vr
T°¤ A
3. Jn(x)¥
3?f
?
exp
?x
2
t? 1t
??
=
1X
n=?1
Jn(x)tn; 0 < jtj < 1:
£
ün5.4? è7
?
?¨Besself
?¥
eBt?é
x17.1 Besself
?¥'?é?3:
4. Jn(x)¥sV
U
Jn(x) = 1…
Z …
0
cos(xsin ?n )d :
£££
3?f
?Vr
T
exp
?x
2
t? 1t
??
=
1X
n=?1
Jn(x)tn
?
7t = ei
1
2
t? 1t
?
= 12 ?ei ?e?i ¢ = isin
eixsin =
1X
n=?1
Jn(x)ein :
?ü
^f
?eixsin ¥FourierZ 7
T(ˉ
??
T)?FourierZ 7¥"
?
Tü?£¤
Jn(x) = 12…
Z …
?…
eixsin
?
ein
·?
d
= 12…
Z …
?…
[cos(xsin ?n )+isin(xsin ?n )]d :
·
s¥$f
??′?
^f
?
?[s10
L?
^}f
?
?[ü?°¤?1
?¥sV
U
?T|$f
??¥?
?n?1?iˉ
?”?"¤?¥i?
^f
?J”(x)¥sV
U
5.?T
3?f
?Vr
T?
7t = iei ? V[¤?
eixcos =
1X
n=?1
Jn(x)inein
=J0(x)+
1X
n=1
h
inJn(x)ein +J?n(x)i?ne?in
i
=J0(x)+
1X
n=1
h
inJn(x)ein +(?)ni?nJn(x)e?in
i
=J0(x)+2
1X
n=1
inJn(x)cosn :
+Y
^?T
7x = kr?
^üμ
eikrcos = J0(kr)+2
1X
n=1
inJn(kr)cosn :
ü
T?¥r? ?31?US"?¥USM
iOük ?31o
?]
H|Mê¥
HWy
01e?i!t5
T
?sY??o?V?Mêy0¥ bW?sP
^?xàZ_.
x17.1 Besself
?¥'?é?4:
l ?¥ü
?oy1
?¥?Mê
?
^
krcos ?!t =è
?;
7·
ò[?¥J0(kr)?Jn(kr)
í
?¥
^?
?o( ??n/
?¥?é8)yN??Z 7
T¥i
lü
^ü
?o??
?oZ 7
[
o
¥?
^?
?¨Besself
?¥?é/
?o
+??é?i¨Besself
??
? ?
6. Besself
?J”(x)?J?”(x)¥Wronski?
T
W [J”(x); J?”(x)] ·
flfl
flfl
fl
J”(x) J?”(x)
J0”(x) J0?”(x)
flfl
flfl
fl = ?
2
…x sin…”:
£££? BesselZ?
1
x
d
dx
?
xdJ”(x)dx
?
+
?
1? ”
2
x2
?
J”(x) = 0;
1
x
d
dx
?
xdJ?”(x)dx
?
+
?
1? ”
2
x2
?
J?”(x) = 0:
[xJ?”(x); xJ”(x)sYe?
?Z?Mh'¤
J?”(x) ddx
?
xdJ”(x)dx
?
?J”(x) ddx
?
xdJ?”(x)dx
?
= ddx
n
x£J?”(x)J0”(x)?J”(x)J0?”(x)?
o
= 0:
?[
J”(x)J0?”(x)?J?”(x)J0”(x) · W [J”(x); J?”(x)] = Cx:
sè
?Cü
^J”(x)J0?”(x)?J?”(x)J0”(x)?x?1[¥"
?
J”(x) =
1X
k=0
(?)k
k!Γ(k +” +1)
?x
2
·2k+”
= 1Γ(” +1)
?x
2
·”
? 1Γ(” +2)
?x
2
·”+2
+¢¢¢
J0”(x) = 1Γ(” +1) ”2
?x
2
·”?1
? 1Γ(” +2) ” +22
?x
2
·”+1
+¢¢¢
J?”(x) =
1X
k=0
(?)k
k!Γ(k?” +1)
?x
2
·2k?”
= 1Γ(?” +1)
?x
2
·?”
? 1Γ(?” +2)
?x
2
·?”+2
+¢¢¢
J0?”(x) = 1Γ(?” +1)?”2
?x
2
·?”?1
? 1Γ(?” +2)?” +22
?x
2
·?”+1
+¢¢¢
?.lZ_??DMê¥
HWy0¥??μ1?T|
HWy01ei!t*
1??ü
?oü
^_μxàZ_.l
¥
x17.1 Besself
?¥'?é?5:
yN
C = 1Γ(” +1) 12” ¢ 1Γ(?” +1) ?”2?” ? 1Γ(?” +1) 12?” ¢ 1Γ(” +1) ”2”
= ? 2”Γ(” +1) Γ(?” +1) = ? 2Γ(”) Γ(1?”)
= ? 2… sin…”:
?[ü£¤
W [J”(x); J?”(x)] = ? 2…x sin…”:
F?” 6=?
?
HW [J”(x); J?”(x)] 6= 0J”(x)?J?”(x)L?í1
F?” =?
?n
HW [Jn(x); J?n(x)] = 0Jn(x)?J?n(x)L?M1
7. Besself
?J”(x)?J?”(x)¥?w1"
d
dx [x
”J”(x)] = x”J”?1(x);
d
dx
£x?”J
”(x)
? = ?x?”J
”+1(x):
£££°¤VBesself
?¥)
?Vr
T???)
??ü
?
l ?
?[ V[?[±
d
dx [x
”J”(x)] = d
dx
1X
k=0
(?)k
k!Γ(k +” +1)
x2k+2”
22k+”
=
1X
k=0
(?)k
k!Γ(k +”)
x2k+2”?1
22k+”?1
=x”J”?1(x):
?ü
^?B
T]"
d
dx
h
x?”J”(x)
i
= ddx
1X
k=0
(?)k
k!Γ(k +” +1)
x2k
22k+”
=
1X
k=1
(?)k
(k?1)!Γ(k +” +1)
x2k?1
22k+”?1
=
1X
k=0
(?)k+1
k!Γ(k +” +2)
x2k+1
22k+”+1
= ?x?”J”+1(x):
?"ü?£
ü
?=
T
V?
??w1"?h?J”(x)J0”(x)? V[¤?
??¥?w1"
J”?1(x)?J”+1(x) = 2J0”(x);
J”?1(x)+J”+1(x) = 2”x J”(x):
x17.1 Besself
?¥'?é?6:
+Y
^
7” = 0
J00(x) = ?J1(x):
8. Besself
?¥víZ 7Besself
?¥víZ 7μ
?'¥ ??B?
a¨?x !
0
J”(x) = 1Γ(” +1)
?x
2
·”
+O
?
x”+2
·
:
? V[°¤?Besself
?¥)
?Vr
T¤?
6B?víZ 7
a¨?x !1
J”(x) ?
r
2
…x cos
?
x? ”…2 ? …4
·
; jargxj < …:
1
I
1J”(x)
í
?¥
^?
?o$
???é5?
?T¥*"
7x = kriOür ?31?US"?¥USM
ük ?31
o
?|
HWy01e?i!t5?r@v
HJ”(kr)
?
í
?¥o?V?¥Mêü
^
cos
?
kr? ”…2 ? …4
·
e?i!t = 12
‰
exp
h
i
?
kr? ”…2 ? …4 ?!t
·i
+exp
h
?i
?
kr? ”…2 ? …4 +!t
·i
;
?Mê
?
^?
?
kr? ”…2 ? …4 currency1!t =è
?;
sY
í
?¥
^?Mê
?
?"
HW? ?v
l
�??
¥?
?o7O??
J”(kr) ?
r
2
…kr cos
?
kr? ”…2 ? …4
·
; jarg(kr)j < …
??cμDpr?Q1¥??y0o?V?¥?
@
áDr?Q1????¥§
?Dr??
1
?[?ê
HW=YV
????
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@V¥9?
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^
a
í
?¥?
^B??
?h¥
?
?o
9.
L
?¨Besself
?¥
,??” > ?11?
?
HJ”(x)μík?
,?
?
ì???
^
L
??1s?
Là
1?J”(x)
,?¥i?? ú?£
o£
üa
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?¨¥Besself
?
?[o3)
?” > ?1¥f?
F J”(x)¥
,?? V?
^B′
?y1?x
^B′
?
HJ”(x)¥ík)
?V
U
^B??[)
?)
??? V?10
x17.1 Besself
?¥'?é?7:
F
!fi
^J”(x)¥B?
,?'J”(fi) = 05fi¥ˉafi?9B?
^J”(x)¥
,?
J”(fi?) = [J”(fi)]? = 0:
'J”(fix)?J”(fi?x) ([x = 11
,?
?
ìsY
?@Z?
1
x
d
dx
?
xdJ”(fix)dx
?
+
?
fi2 ? ”
2
r2
?
J”(fix) = 0;
1
x
d
dx
?
xdJ”(fi
?x)
dx
?
+
?
fi?2 ? ”
2
r2
?
J”(fi?x) = 0:
|
?Z?sYe[xJ”(fi?x)?xJ”(fix)MhuW[0; 1]
s'¤
?
fi2 ?fi?2
·Z 1
0
xJ”(fix)J”(fi?x)dx
= ?x
?
J”(fi?x)dJ”(fix)dx ?J”(fix)dJ”(fi
?x)
dx
?flfl
flfl
1
0
= 0:
??
xJ”(fix)J”(fi?x) = xjJ”(fix)j2 ? 0;
O??10
?[?” > ?1
Hs
Z 1
0
xJ”(fix)J”(fi?x)dx 6= 0;
?"ü£¤
fi2 = fi?2;
'fi2
^
L
?
F?
Hμ
? V?
fi2 ? 0'fi1
L
?
?
fi2 < 0'fi1B′
?
???fi? V?1B′
?
?[fiB?
^
L
?
FB?J”(fi) = 05?J”(x)¥)
?Vr
T V[ A9B?μJ”(?fi) = 0
?[J”(x)¥
,??1s?
Là
÷éB?? ?w1"?Rolle? ?ü V[??J”(x)¥M
#¥
?
,?-WA?
μJ”§1(x)¥B?
,?
x17.2 Neumannf
??8:
x17.2 Neumannf
?
F BesselZ?¥
?3J§”(x)?” 6=?
?
H
^L?í1¥
W [J”(x); J?”(x)] = ? 2…x sin…”;
Z?¥Y3 V[V
U1J§”(x)¥L?F?
F?” =?
?n
HJ§n(x)
^L?M1¥yN?31×?pZ?¥?=3
FVe5
?
aK'¥÷E
^|?=31c
?[¥?53}?Z??"
?
F1?F
ó¥÷E
^?” 6=?
?
Hü?=39?
^e?1|1J?”(x)7
^ˉ?|
1J§”(x)¥L?F??? V[
a?1ê4F?"
? è?|
y2(x) = cJ”(x)?J?”(x)sin”… ;
üB?μ
W [J”(x); y2(x)] = 2…x:
?"'
P” !?
?ny2(x)ˉ?DJn(x)L?í1
F?” !?
?n
H3
Ty2(x)¥ssin”… ! 0yN?A?
a?ê4
6B?F?"
?c
P¤y2(x)¥s09M103
T? V?μil
F I
n?
J?n(x) = (?)nJn(x) = cosn…Jn(x);
# V|c = cos”…
?"ü?l
Neumannf
? ?
N”(x) = cos”…J”(x)?J?”(x)sin”… ;
?
?”
^?1?
?
?9 V[|1BesselZ?¥?=3
?
?¨¥Neumannf
?Nn(x)?? ?31” ! n
HN”(x)¥K
Nn(x) = lim”!n cos”…J”(x)?J?”(x)sin”…
= 1…
?@J
”(x)
@” ?(?)
n@J?”(x)
@”
?
”=n
= 2…Jn(x)ln x2 ? 1…
n?1X
k=0
(n?k?1)!
k!
?x
2
·2k?n
? 1…
1X
k=0
(?)k
k!(n+k)!
£?(n+k +1)
+?(k +1)?
?x
2
·2k+n
; jargxj < …:
?μ¥óD?9TY”(x)
x17.2 Neumannf
??9:
iO???n = 0
H1??·
?=[¥μK?
?x ! 0; Re” > 0
HN”(x)¥ví?1???J?”(x) %?
N”(x) ??Γ(”)…
?x
2
·?”
:
7?N0(x)
N0(x) ? 2… ln x2:
?[?
?”
^?1?
?N”(x)x = 0??
^??¥
?x !1
HNeumannf
?¥víVr
T
^
N”(x) ?
r
2
…x sin
?
x? ”…2 ? …4
·
; jargxj < …:
yNN”(x)9 V[¨ ?
í?
?o]"9
^??¥?
?o??
¥?
?o¥?F
N”(x)¥?w1"¥?
T?Besself
???M]
d
dx [x
”N”(x)] = x”N”?1(x);
d
dx
£x?”N
”(x)
? = ?x?”N
”+1(x):
Besself
???1?B ??f
?Neumannf
???1?= ??f
?
N0(x); N1(x)?N2(x)¥m?nm17.2
m17.2 `Neumannf
?
?
N
Hankel9;üBesselZ?¥?=3|1
J”(z)?(?)nJ?”(z)
” ?n :
?” ! n
H
lim”!n J”(z)?(?)
nJ?”(z)
” ?n = lim”!n
?J
”(z)?Jn(z)
” ?n ?(?)
nJ?”(z)?J?n(z)
” ?n
?
=
?@J
”(z)
@” ?(?)
n@J?”(z)
@”
?
”=n
=…Nn(z):
(Watson, x 3.5)
x17.2 Neumannf
??10:
Zeros of the functions J”(z) & N”(z)
1. Real zeros
When ” is real, the functions J”(z) & N”(z) each have an infinite number of zeros, all of
which are simple with the possible exception of z = 0. For non-negative ” the sth positive
zeros of these functions are denoted by j”;s and n”;s respectively.
s j0;s j1;s n0;s n1;s
1 2.40483 3.83171 0.89358 2.19714
2 5.52008 7.01559 3.95768 5.42968
3 8.65373 10.17347 7.06805 8.59601
4 11.79153 13.32369 10.22235 11.74915
5 14.93092 16.47063 13.36110 14.89744
6 18.07106 19.61586 16.50092 18.04340
7 21.21164 22.76008 19.64131 21.18807
8 24.35247 25.90367 22.78203 24.33194
9 27.49348 29.04683 25.92296 27.47529
10 30.63461 32.18968 29.06403 30.61829
2. McMahon’s expansions for large zeros
j”;s;n”;s ? fl ? ??18fl ? 4(??1)(7??31)3(8fl)3
?32(??1)(83?
2 ?982?+3779)
15(8fl)5
?64(??1)(6949?
3 ?153855?2 +1585743??6277237)
105(8fl)7
?¢¢¢¢¢¢ ; s ”; ? = 4”2;
fl =
s+ ”2 ? 14
?
…; for j”;s
fl =
s+ ”2 ? 34
?
…; for n”;s
3. Complex zeros of J”(z)
When ” ? ?1 the zeros of J”(z) are all real. If ” < ?1 and ” is not an integer the
number of complex zeros of J”(z) is twice the integer part of (?”); if the integer part of (?”)
is odd two of these zeros lie on the imaginary axis.
4. Complex zeros of N”(z)
When ” is real the pattern of the complex zeros of N”(z) depends on the non-integer
part of ”. Attention is confined here to the case ” = n, a positive integer or zero.
x17.2 Neumannf
??11:
Zeros of Nn(z)
The figure above shows the approximate distribution of the complex zeros of Nn(z) in
the region jargzj? …. The figure is symmetrical about the real axis. The two curves on the
left extend to infinity, having the asymptotes
Imz = §12 ln3 = §0:54931::::::
There are an infinite number of zeros near each of these curves.
The two curves extending from z = ?n to z = n and bounding an eye-shaped domain
intersect the imaginary axis at the points §i(na+b), where
a =
q
t20 ?1 = 0:66274::::::
b = 12
q
1?t?20 ln2 = 0:19146::::::
and t0 = 1:19968:::::: is the positive root of cotht = t. There are n zeros near each of these
curves.
Complex zeros of N0(z) Complex zeros of N1(z)
Real part Imaginary part Real part Imaginary part
?2:40302 0:53988 ?0:50274 0:78624
?5:51988 0:54718 ?3:83353 0:56236
?8:65367 0:54841 ?7:01590 0:55339
x17.3?f
??12:
x17.3?f
?
O
^
?@?w1"
d
dx [x
”C”(x)] =x”C”?1(x);
d
dx
h
x?”C”(x)
i
= ?x?”C”+1(x)
¥f
?fC”(x)gd?1?f
?-
?o
¥Besself
??Neumannf
??
^?f
?
???fff
?
?
?BBB???
^
^
^BesselZZZ???¥¥¥333
n5ü?w1"??
C0”(x)+ ”xC”(x) = C”?1(x) (z)
C0”(x)? ”xC”(x) = ?C”+1(x): (#)
|(z)
T±
¤
C00”(x)+ ”xC0”(x)? ”x2C”(x) = C0”?1(x): (##)
|(#)
T?¥”?1” ?1i|(z)
T}?
C0”?1(x) = ” ?1x C”?1(x)?C”(x)
= ” ?1x
h
C0”(x)+ ”xC”(x)
i
?C”(x):
}?(##)
T'¤
C00”(x)+ ”xC0”(x)? ”x2C”(x) = ” ?1x C0”(x)+ ”(” ?1)x2 C”(x)?C”(x);
F? ?ü¤?
C00”(x)+ 1xC0”(x)+
1? ”
2
x2
?
C”(x) = 0:
?ü£
ü
?f
?fC”(x)gB?
^BesselZ?¥3
x17.4 BesselZ?¥'?′ù5?13:
x17.4 BesselZ?¥'?′ù5
p
1?%?¥??
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q
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¥???"ê±sZ??H?Hqü
^
@2u
@t2 ?c
2
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r
@
@r
r@u@r
?
+ 1r2 @
2u
@`2
?
= 0;
uflflr=0μ?, uflflr=a = 0;
uflfl`=0 = uflfl`=2…, @u@`
flfl
flfl
`=0
= @u@`
flfl
flfl
`=2…
:
ù5C¥3u μ??M?(D`í1)
?$
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^H?Hq¥K?/??? V*t!′
P¤Z?μd
,3
u(r;`;t) = v(r;`)ei!t:
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T}?Z?#H?Hqü V[¤?
1
r
@
@r
r@v@r
?
+ 1r2 @
2v
@`2 +
?!
c
·2
v = 0;
vflflr=0μ?vflflr=a = 0;
vflfl`=0 = vflfl`=2…, @v@`
flfl
flfl
`=0
= @v@`
flfl
flfl
`=2…
:
7v(r;`) = R(r)'(`)s ?M
ü¤?
?'?′ù5
'00(`)+m2'(`) = 0;
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?
1
r
d
dr
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rdR(r)dr
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+
k2 ? m
2
r2
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?B?'?′ù5XüQn?V??
?¥'?′
m2; m = 0;1;2;3;¢¢¢ ;
x17.4 BesselZ?¥'?′ù5?14:
'?f
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‰cosm`;
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p3?=?'?′ù5
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Hè±sZ?¥Y3
^
R(r) = C0rm +D0r?m:
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yNk = 0?
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?¥
Y3
R(r) = CJm(kr)+DNm(kr):
I
n?H?Hq¥1p
R(0)μ?) D = 0;
R(a) = 0; ) Jm(ka) = 0:
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¥3
^
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q
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a c;
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1
r
d
dr
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L
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a ???μJm(ka) = 0
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0
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flfl
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r=0
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0
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^'?′ù5¥37Z 7"
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Z a
0
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Z a
0
J2m(kir)rdr
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rdr:
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1
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r@u@r
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flfl
fl
r=a
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flfl
fl
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x17.4 BesselZ?¥'?′ù5?19:
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u(r;t) = R(r)e?i!t;
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r
d
dr
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?
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H'?′ù5í3?
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R(r)7|Z??1BesselZ??N' V¤?
R(r) = CJ1(kr)+DN1(kr):
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CJ1(ka)+DN1(ka) = 0; CJ01(kb)+DN01(kb) = 0:
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flflJ1(ka) N1(ka)
J01(kb) N01(kb)
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v1(r;`) = E0eikrcos`;
?
¥Z_|1xà('` = 0)¥Z_v1(r;`)
?@HelmholtzZ?
1
r
@
@r
r@v1@r
?
+ 1r2 @
2v1
@`2 +k
2v1 = 0;
F?
ov2(r;`)9
?@HelmholtzZ?
1
r
@
@r
r@v2@r
?
+ 1r2 @
2v2
@`2 +k
2v2 = 0:
1
p3v2(r;`)?A?
v2(r;`)
?
?@¥H?Hq
n5
???
?@?ùHq
v2(r;`)flfl`=0 = v2(r;`)flfl`=2…;
@v2(r;`)
@`
flfl
fl
`=0
= @v2(r;`)@`
flfl
fl
`=2…
:
QL
!?8V
?
^ ?X?8è?<?
?r = a
¥M_s
10
?[
u(r;`;t)flflr=a = 0;
?N V[?
v2(r;`)flflr=a = ?E0eikacos`:
KaíkùHq5
^v2(r;`)
^_íkù?
¥?
?o'
v2(r;`)flflr!1?ocμ?
o¥?s:
?¥ê±sZ?(HelmholtzZ?)?H?Hqü?
B???¥?3ù5?vs ?
M
E¥S?? V[
?@Z???ùHq#íkùHq¥B?3
v2(r;`) =
1X
m=0
(Am cosm`+Bm sinm`)H(1)m (kr):
}?
:/¥H?Hqü¤?
v2(r;`)flflr=a =
1X
m=0
(Am cosm`+Bm sinm`)H(1)m (ka)
= ?E0eikacos`
= ?E0J0(ka)?2E0
1X
m=1
imJm(ka)cosm`:
?¥KaB?¨?
eikrcos = J0(kr)+2
1X
n=1
inJn(kr)cosn :
x17.6 Hankelf
??26:
1?"
?ü¤?
A0 = ?E0 J0(ka)
H(1)0 (ka)
;
Am = ?2E0im Jm(ka)
H(1)m (ka)
, m = 1;2;3;¢¢¢ ;
Bm = 0, m = 1;2;3;¢¢¢ :
?
^?
oè
O
¥ bW?sü
^
v2(r;`) = ?E0J0(ka)
H(1)0 (ka)
H(1)0 (kr)?2E0
1X
m=1
im Jm(ka)
H(1)m (ka)
H(1)m (kr)cosm`:
Kaüp¤
u(r;`;t) = E0ei(krcos`?!t) ? E0J0(ka)
H(1)0 (ka)
H(1)0 (kr)e?i!t
?2E0e?i!t
1X
m=1
im Jm(ka)
H(1)m (ka)
H(1)m (kr)cosm`:
x17.7′7
Besself
??27:
x17.7′7
Besself
?
C)
?+ ?+
y¥Besself
?,
n5
^+
y7
¥Besself
?,7
1B′
?¥Bessel
f
?
?^ˉVê±sZ?¥?3ù5? ???′7
¥Besself
?
!μ??8=¥LaplaceZ??3ù5
1
r
@
@r
r@u@r
?
+ 1r2 @
2u
@`2 +
@2u
@z2 = 0;
uflfl`=0 = uflfl`=2…, @u@`
flfl
fl
`=0
= @u@`
flfl
fl
`=2…
;
uflflz=0 = 0, uflflz=h = 0;
uflflr=0μ?, uflflr=a = f(`;z):
?vs ?M
E¥SSE
7
u(r;`;z) = R(r)'(`)Z(z);
}?Z?#H?Hqs ?M
ü?¤?'?′ù5
'00(`)+?'(`) = 0;
'(0) = '(2…), '0(0) = '0(2…)
?
Z00(z)+?Z(z) = 0;
Z(0) = 0, Z(h) = 0
[#è±sZ?
1
r
d
dr
rdRdr
?
+
?
??? ?r2
·
R = 0:
??B?'?′ù5 V[¤?
'?′?m = m2, m = 0;1;2;3;¢¢¢ ;
'?f
?'m(`) = Am cosm`+Bm sinm`;
?Am?Bm
^?iè
???=?'?′ù5? V[p¤
'?′?n =
?n…
h
·2
, n = 1;2;3;¢¢¢ ;
'?f
?Zn(z) = sin n…h z:
?"
:/¥è±sZ?üM?
1
r
d
dr
rdRdr
?
+
?
?
?n…
h
·2
? m
2
r2
?
R = 0:
x17.7′7
Besself
??28:
TMDx = (n…=h)r?y(x) = R(r)ü V[|NZ??1
1
x
d
dx
xdydx
?
+
?
?1? m
2
x2
·
y = 0:
??Z??1′7
BesselZ?TMDt = ixü V[|
??1BesselZ??
^
R(r) = CJm
in…
h r
?
+DNm
in…
h r
?
:
? úüC
7
1B′
?¥Besself
??Neumannf
?
B?
a ??Besself
?¥7
1B′
?xei…=2(?x1
L
?)
Hf
?′9
^ˉ
?
J”(xei…=2) =
1X
k=0
(?)k
k!Γ(k +” +1)
?x
2e
i…=2·2k+”
= ei”…=2
1X
k=0
1
k!Γ(k +” +1)
?x
2
·2k+”
:
?"L?^?l?B ?′7
Besself
?
I”(x) · e?i”…=2J”(xei…=2) =
1X
k=0
1
k!Γ(k +” +1)
?x
2
·2k+”
:
+Y
^??
?¨¥?B ?′7
Besself
?e?1μ
In(x) = i?nJn(ix):
?"S¥"¥
Es
üA
P¤x?”?
^
L
?
HI”(x)¥f
?′?
^
L
?
]"??I”(x)?I?”(x)?
^]B?′7
BesselZ?¥37O I
n?
I?n(x) = inJ?n(ix)
= (?)ninJn(ix)
= i?nJn(ix)
= In(x)
V[?l?= ?′7
Besself
?1
K”(x) = …2sin”…
h
I?”(x)?I”(x)
i
:
???l¥z)
^?”1?
?n
HKn(x)ˉ?μilODIn(x)L?í1
Kn(x) = lim”!nK”(x)
= 12
n?1X
k=0
(?)k(n?k?1)!k!
?x
2
·2k?n
+(?)n+1
1X
k=0
‰ 1
k!(n+k)!
h
ln x2 ? 12?(n+k +1)
?12?(k +1)
i?x
2
·2k+n
:
x17.7′7
Besself
??29:
? úˉ???n = 0
H???·
?B[¥μK?
m17.4 `′7
Besself
?
?
?ó¥I”(x)?K”(x)¥?l?^
?
ìx ! 0
H¥ví?1
F?T” ? 05
? I”(x)
^μ?¥
? K”(x)
^í?¥
F?x !1
H
?
ì¥ví?1?
^
I”(x) ?
r
1
2…xe
x; K”(x) ?
r …
2xe
?x:
L¨?èè? ?tví?1Gê
?31¥3 è?
?¥?3ù5
1
r
@
@r
r@u@r
?
+ 1r2 @
2u
@`2 +
@2u
@z2 = 0;
uflfl`=0 = uflfl`=2…, @u@`
flfl
fl
`=0
= @u@`
flfl
fl
`=2…
;
uflflz=0 = 0, uflflz=h = 0;
uflflr=0μ?, uflflr=a = f(`;z):
?üB?μ+3
umn(r;`;z) = (Am cosm`+Bm sinm`)
£
h
CmnIm
?n…
h r
·
+DmnKm
?n…
h r
·i
sin n…h z:
??μ?Hq
uflflr=0μ?
¥K?
Dmn = 0:
x17.7′7
Besself
??30:
?
^H?Hq?μ?Hq¥K?/Z?¥+3ü
^
umn(r;`;z) = (Amn cosm`+Bmn sinm`) Im
?n…
h r
·
sin n…h z:
|?ík?+3?F ?¤?B?3?a ?¨d
QH?Hq' V??F"
?
x17.8?
?¨Besself
??31:
x17.8?
?¨Besself
?
)
?
6B ?+
y¥Besself
? μ+
y¨
?¥Besself
?¨1?
?¥Besself
?
5)
?J1=2(x)
J1=2(x) =
1X
k=0
(?)k
k!Γ(k +3=2)
?x
2
·2k+1=2
=
r
2
…x
1X
k=0
(?)k
(2k +1)!x
2k+1:
?[
J1=2(x) =
r
2
…x sinx
^?f
?
L=
?iB??
?¨¥Besself
??
^?f
??
^
af
????f
?¥ˉ?f
?? V[V?w1" ?£
ü
n5ü?w1"
d
dx [x
”J”(x)] = x”J”?1(x)
??
1
x
d
dx
?
x”J”(x) = x”?1J”?1(x);
?[
1
x
d
dx
?n
x1=2J1=2(x) =
1
x
d
dx
?nr2
… sinx
= x?n+1=2J?n+1=2(x):
yNJ?n+1=2(x)?
^?f
?+Y
^
J?1=2(x) =
r
2
…x cosx:
]"ü?w1"
d
dx
h
x?”J”(x)
i
= ?x?”J”+1(x)
??
1
x
d
dx
?
x?”J”(x) = ?x?(”+1)J”+1(x);
?[
1
x
d
dx
?n
x?1=2J1=2(x) =
1
x
d
dx
?nr2
…
sinx
x
= (?)nx?n?1=2Jn+1=2(x):
x17.8?
?¨Besself
??32:
yNJn+1=2(x)9?
^?f
?
A?Jn+1=2(x)DJ?(n+1=2)(x)
^L?í1¥
W[Jn+1=2(x); J?(n+1=2)(x)]
= ? 2…x sin
?
n+ 12
·
… = (?)n+1 2…x:
7Nn+1=2(x)DJ?(n+1=2)(x)L?M1
Nn+1=2(x) = cos(n+1=2)… ¢Jn+1=2(x)?J?(n+1=2)(x)sin(n+1=2)…
=(?)n+1J?(n+1=2)(x):
x17.9oBesself
??33:
x17.9oBesself
?
á
ìoUS"/|HelmholtzZ?r2u+k2u = 0s ?M
u(r; ;`) = R(r)£( )'(`);
;ü¤???è±sZ?
'00 +?' = 0;
1
sin
d
d
?
sin d£d
?
+
h
?? ?sin2
i
£ = 0;
1
r2
d
dr
r2dRdr
?
+
h
k2 ? l(l +1)r2
i
R = 0:
B?f ?/?B?Z??M?¥?ùHq?'?′ù5 V[?'?′
?m = m2; m = 0;1;2;¢¢¢ :
?=?Z??M?¥μ?Hq?'?′ù5?'?′
?l = l(l +1); l = m;m+1;m+2;¢¢¢ :
?B?)
????Z?¥p3ù5
?A)
?k = 0¥f?y1?
H¥p3ù5
BcXü)
?V
?¥
?L?
í13ü
^rl?r?l?1
y1k 6= 0# VTMDx = kr?y(x) = R(r)|Z?M1
1
x2
d
dx
x2dydx
?
+
h
1? l(l +1)x2
i
y(x) = 0:
??Z??1oBesselZ?
oBesselZ?¥?
T?BesselZ?dèM
?éB?sZ?¥? V[ A?
oBesselZ?9μ
??
FB?
^x = 0?5?
FB?
^x = 1d?5?
9?BesselZ?M]yN V[
km|
??1BesselZ?
I
n???Z?x = 0?¥·SZ?
‰(‰?1)+2‰?l(l +1) = 0;
y7·S1‰1 = l?‰2 = ?(l + 1)?BesselZ?¥·S‰ = §”¥+?‰1 + ‰2 = 0?]#?
?TMD
y(x) = v(x)px ;
x17.9oBesself
??34:
?" V[?
v(x)¥±sZ?x = 0?¥·Sü?M1
‰ = §
l + 12
?
;
?BesselZ?¥+???B"
?MD/
dy
dx =
1p
x
?dv
dx ?
1
2
v
x
?
;
d
dx
x2dydx
?
= 1px
?
x ddx
xdvdx
?
? v4
?
;
?[v(x)
?
?@¥±sZ?ü
^
1
x
d
dx
xdvdx
?
+
?
1? (l +1=2)
2
x2
?
v = 0:
??
^l+1=2¨¥BesselZ?
?¥
?L?í13ü
^Jl+1=2(x)?Nl+1=2(x)N$
ü V[|oBesselZ?¥L?í13|1
jl(x) =
r …
2xJl+1=2(x)
=
r …
2x
1X
n=0
(?)n
n!Γ(n+l +3=2)
?x
2
·2n+l+1=2
=
p…
2
1X
n=0
(?)n
n!Γ(n+l +3=2)
?x
2
·2n+l
?
nl(x) =
r …
2xNl+1=2(x) = (?)
l+1
r …
2xJ?(l+1=2)(x)
= (?)l+1
r …
2x
1X
n=0
(?)n
n!Γ(n?l +1=2)
?x
2
·2n?l?1=2
= (?)l+1
p…
2
1X
n=0
(?)n
n!Γ(n?l +1=2)
?x
2
·2n?l?1
;
sY?1l¨oBesself
??oNeumannf
?
-+?oBesself
??oNeumannf
?¥Vr
T
^
j0(x) = sinxx ;
j1(x) = 1x2?sinx?xcosx¢;
j2(x) = 1x3
h?
3?x2¢sinx?3xcosx
i
;
n0(x) = ?cosxx ;
n1(x) = ? 1x2?cosx+xsinx¢;
n2(x) = ? 1x3
h?
3?x2¢cosx+3xsinx
i
:
x17.9oBesself
??35:
m17.5 `oBesself
?
?
?19? V[?loHankelf
?
h(1)l (x) = jl(x)+inl(x); h(2)l (x) = jl(x)?inl(x):
?w1"
1
x
d
dx
?nh
xl+1jl(x)
i
= xl?n+1jl?n(x);
1
x
d
dx
?nh
x?ljl(x)
i
= (?)nx?l?njl+n(x);
jl?1(x)+jl+1(x) = 2l +1x jl(x);
ljl?1(x)?(l +1)jl+1(x) = (2l +1)j0l(x);
l +1
x +
d
dx
?
jl(x) = jl?1(x);
l
x ?
d
dx
?
jl(x) = jl+1(x):
è è è4|f
?eikrcos ?Legendre[
TZ 7
333
!
eikrcos =
1X
l=0
cl(kr)Pl(cos );
5Z 7"
?
cl(kr) = 2l +12
Z 1
?1
eikrxPl(x)dx = 2l +12
1X
n=0
(ikr)n
n!
Z 1
?1
xnPl(x)dx:
x17.9oBesself
??36:
?¨16.4?¥2Tüμ
cl(kr) = 2l +12
1X
n=0
(ikr)l+2n
(l +2n)!
Z 1
?1
xl+2nPl(x)dx
= 2l +12 il
1X
n=0
(?)n
(l +2n)!(kr)
l+2n ¢ (l +2n)!
2l+2nn!
p…
Γ(n+l +3=2)
= 2l +12 ilp…
1X
n=0
(?)n
n!Γ(n+l +3=2)
kr
2
?l+2n
= (2l +1)il jl(kr):
?[KaüμZ 7
T
eikrcos =
1X
l=0
(2l +1)il jl(kr)Pl(cos ):
9 V[?í??Z 7
TB?t ?3
dü
?o?o
?oZ 7?
^y1?T?
?Mê¥
HWy01e?i!t7Oür? ?31oUS5
TP
^_ = 0('
?zà)Z_.l¥ü
?oo
?1k7·
?B[?¥jl(kr)5 μo
?o¥Mê
y0
jl(kr) ? 1kr sin
kr? l…2
?
: