{"id":2751,"date":"2022-03-29T17:41:16","date_gmt":"2022-03-29T08:41:16","guid":{"rendered":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/?page_id=2751"},"modified":"2026-01-16T11:53:44","modified_gmt":"2026-01-16T02:53:44","slug":"%e6%99%82%e9%96%93%e5%a4%89%e5%8b%95%e3%81%97%e3%81%aa%e3%81%84%e9%9b%bb%e7%a3%81%e5%a0%b4%e3%81%ae%e3%81%be%e3%81%a8%e3%82%81","status":"publish","type":"page","link":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/%e9%9b%bb%e7%a3%81%e6%b0%97%e5%ad%a6-i\/%e6%99%82%e9%96%93%e5%a4%89%e5%8b%95%e3%81%97%e3%81%aa%e3%81%84%e9%9b%bb%e7%a3%81%e5%a0%b4%e3%81%ae%e3%81%be%e3%81%a8%e3%82%81\/","title":{"rendered":"\u6642\u9593\u5909\u52d5\u3057\u306a\u3044\u96fb\u78c1\u5834\u306e\u307e\u3068\u3081"},"content":{"rendered":"

\u3053\u308c\u307e\u3067\u306e\u3068\u3053\u308d\u3092\u307e\u3068\u3081\u3066\u304a\u304f\u3002
\n<\/p>\n

\u30de\u30af\u30b9\u30a6\u30a7\u30eb\u65b9\u7a0b\u5f0f<\/a><\/h3>\n

\\begin{eqnarray}
\n\\nabla\\cdot \\boldsymbol{D} &=& \\rho \\quad \\tag{1}\\\\
\n\\nabla\\cdot\\boldsymbol{B} &=& 0 \\quad \\tag{2}\\\\
\n\\nabla\\times\\boldsymbol{E} + \\color{red}{\\frac{\\partial \\boldsymbol{B}}{\\partial t} }&=& \\boldsymbol{0} \\quad \\tag{3}\\\\
\n\\nabla\\times\\boldsymbol{H} -\\color{red}{\\frac{\\partial \\boldsymbol{D}}{\\partial t} }&=& \\boldsymbol{J} \\quad \\tag{4}\\end{eqnarray}<\/p>\n

\u6642\u9593\u5909\u52d5\u3057\u306a\u3044\u96fb\u78c1\u5834\u306e\u5834\u5408\u306f\u8d64\u5b57\u306e\u90e8\u5206\u304c\u6d88\u3048\u3066<\/p>\n

\\begin{eqnarray}
\n\\nabla\\cdot \\boldsymbol{D} &=& \\rho \\quad \\tag{1}\\\\
\n\\nabla\\cdot\\boldsymbol{B} &=& 0 \\quad \\tag{2}\\\\
\n\\nabla\\times\\boldsymbol{E} &=& \\boldsymbol{0} \\quad \\tag{3a}\\\\
\n\\nabla\\times\\boldsymbol{H} &=& \\boldsymbol{J} \\quad \\tag{4a}\\end{eqnarray}<\/p>\n

\u9759\u96fb\u5834\u306e\u57fa\u672c\u65b9\u7a0b\u5f0f<\/a><\/h3>\n

$\\boldsymbol{D} = \\varepsilon_0 \\boldsymbol{E}$ \u3092\u4f7f\u3063\u3066 $\\boldsymbol{E}$ \u3060\u3051\u306e\u5f0f\u306b\u3057\u3066\uff0c$(\\mbox{1})$ \u5f0f\u3068 $(\\mbox{3a})$ \u5f0f\u306f<\/p>\n

$$\\nabla\\cdot \\boldsymbol{E} = \\frac{\\rho}{\\varepsilon_0},
\n\\quad \\nabla\\times\\boldsymbol{E} = \\boldsymbol{0}$$<\/p>\n

\u9759\u78c1\u5834\u306e\u57fa\u672c\u65b9\u7a0b\u5f0f<\/a><\/h3>\n

$\\boldsymbol{H} = \\frac{1}{\\mu_0} \\boldsymbol{B}$ \u3092\u4f7f\u3063\u3066 $\\boldsymbol{B}$ \u3060\u3051\u306e\u5f0f\u306b\u3057\u3066\uff0c$(\\mbox{2})$ \u5f0f\u3068 $(\\mbox{4a})$ \u5f0f\u306f<\/p>\n

$$ \\nabla\\cdot\\boldsymbol{B} = 0, \\quad \\nabla\\times\\boldsymbol{B}= \\mu_0\\,\\boldsymbol{J} = \\frac{\\boldsymbol{J} }{\\varepsilon_0 c^2}$$<\/p>\n

$\\displaystyle \\varepsilon_0 \\mu_0 = \\frac{1}{c^2}$ \u3068\u306a\u308b\u7406\u5c48\u306f\u3053\u306e\u3078\u3093<\/a><\/strong><\/span>\u306b\u307e\u3068\u3081\u3066\u304a\u3044\u305f\u3002<\/p>\n

\u96fb\u78c1\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb<\/h3>\n

$$\\nabla\\times\\boldsymbol{E} = \\boldsymbol{0} \\quad\\Rightarrow\\quad\u00a0 \\boldsymbol{E} \\equiv -\\nabla\\phi$$<\/p>\n

 <\/p>\n

$$\\nabla\\cdot\\boldsymbol{B} = 0 \\quad\\Rightarrow\\quad \\boldsymbol{B} \\equiv \\nabla\\times\\boldsymbol{A}$$<\/p>\n

\u3068\u3044\u3046\u3088\u3046\u306b\u30b9\u30ab\u30e9\u30fc\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb<\/strong><\/span>\uff08\u9759\u96fb\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb\uff09\\(\\phi\\) \u3068\u30d9\u30af\u30c8\u30eb\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb<\/strong><\/span> \\(\\boldsymbol{A}\\) \u3092\u5c0e\u5165\u3067\u304d\u305f\u3002<\/p>\n

\\(\\phi\\) \u3068 \\(\\boldsymbol{A}\\) \u3092\u307e\u3068\u3081\u3066\u96fb\u78c1\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb<\/strong><\/span>\u3068\u547c\u307c\u3046\u3002\u307e\u305f\uff0c\u4eca\u5f8c\uff0c\u9759\u96fb\u5834\uff08\u6642\u9593\u5909\u52d5\u3057\u306a\u3044\u96fb\u5834\uff09\u3067\u306a\u3044\u5834\u5408\u306b\u3064\u3044\u3066\u3082\u8ff0\u3079\u308b\u306e\u3067\uff0c\u4e00\u6642\u300c\u9759\u96fb\u300d\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb\u3068\u3082\u547c\u3093\u3067\u3044\u305f \\(\\phi\\) \u306e\u547c\u79f0\u3092\u300c\u30b9\u30ab\u30e9\u30fc\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb<\/strong><\/span>\u300d\u306b\u7d71\u4e00\u3059\u308b\u3002<\/p>\n

\u30b2\u30fc\u30b8\u6761\u4ef6<\/h3>\n

\u30d9\u30af\u30c8\u30eb\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb \\(\\boldsymbol{A}\\) \u306b\u5bfe\u3057\u3066\uff0c\u30af\u30fc\u30ed\u30f3\u30b2\u30fc\u30b8\u6761\u4ef6<\/strong><\/span>
\n$$\\nabla\\cdot\\boldsymbol{A} = 0$$
\n\u3092\u8ab2\u3059\u3068…<\/p>\n

\u30dd\u30a2\u30bd\u30f3\u65b9\u7a0b\u5f0f<\/a><\/h3>\n

\u96fb\u78c1\u30dd\u30c6\u30f3\u30b7\u30e3\u30eb\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30dd\u30a2\u30bd\u30f3\u65b9\u7a0b\u5f0f<\/strong><\/span>\u306b\u5f93\u3046\u3053\u3068\u304c\u308f\u304b\u308a\uff0c
\n$$\\nabla^2 \\phi = -\\frac{\\rho}{\\varepsilon_0}, \\quad\u00a0 \\nabla^2 \\boldsymbol{A} = -\\frac{\\boldsymbol{J}}{\\varepsilon_0c^2}$$
\n\u305f\u3060\u3061\u306b\u5b8c\u5168\u306a\u89e3\u304c\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u6c42\u307e\u308b\u306e\u3067\u3042\u3063\u305f\u3002<\/p>\n

\\begin{eqnarray}
\n\\phi(\\boldsymbol{r}) &=& \\frac{1}{4\\pi\\varepsilon_0} \\iiint \\frac{\\rho(\\boldsymbol{r}’)}{|\\boldsymbol{r} -\\boldsymbol{r}’|} dV’
\n\\end{eqnarray}<\/p>\n

$$ \\boldsymbol{A} (\\boldsymbol{r})= \\frac{1}{4\\pi \\varepsilon_0 c^2} \\iiint \\frac{\\boldsymbol{J}(\\boldsymbol{r}’)}{|\\boldsymbol{r} -\\boldsymbol{r}’|} \\,dV’$$<\/p>\n

\u96fb\u8377\u5bc6\u5ea6\u304b\u3089\u76f4\u63a5\u9759\u96fb\u5834\u3092\u6c42\u3081\u308b\u5f0f<\/a><\/h3>\n

\\begin{eqnarray}
\\boldsymbol{E} (\\boldsymbol{r}) &=& -\\nabla\\phi (\\boldsymbol{r})
= \\frac{1}{4\\pi \\varepsilon_0} \\iiint\\frac{\\rho(\\boldsymbol{r}’) (\\boldsymbol{r} -\\boldsymbol{r}’) }{|\\boldsymbol{r} -\\boldsymbol{r}’|^3}dV’
\\end{eqnarray}<\/p>\n

\u3053\u306e\u7a4d\u5206\u304c\uff08\u6bd4\u8f03\u7684\uff09\u7c21\u5358\u306b\u3067\u304d\u308b\u3044\u304f\u3064\u304b\u306e\u4f8b\u3092\u4ee5\u4e0b\u306b\u307e\u3068\u3081\u308b\u3002<\/p>\n

\u70b9\u96fb\u8377\u306e\u96fb\u8377\u5bc6\u5ea6\u3068\u96fb\u5834<\/a><\/h4>\n

\u4f4d\u7f6e $\\boldsymbol{r}_1$ \u306b\u304a\u3044\u305f\u70b9\u96fb\u8377 $q_1$ \u306e\u96fb\u8377\u5bc6\u5ea6\u306f\uff0c\u30c7\u30a3\u30e9\u30c3\u30af\u306e\u30c7\u30eb\u30bf\u95a2\u6570\u3092\u4f7f\u3063\u3066<\/p>\n

$$\\rho(\\boldsymbol{r}) = q_1 \\, \\delta^3(\\boldsymbol{r} -\\boldsymbol{r}_1)$$<\/p>\n

\u96fb\u5834\u306f<\/p>\n

$$\\boldsymbol{E} = \\frac{q_1}{4\\pi \\varepsilon_0} \\frac{ \\boldsymbol{r}\u00a0 -\\boldsymbol{r}_1}{|\\boldsymbol{r}\u00a0 -\\boldsymbol{r}_1|^3} $$<\/p>\n

\u7279\u306b\u70b9\u96fb\u8377\u304c\u539f\u70b9\u306b\u3042\u308b\u5834\u5408\u306f $\\boldsymbol{r}_1 = \\boldsymbol{0}$ \u3068\u3059\u308c\u3070\u3044\u3044\u3057\uff0c\u8907\u6570\u306e\u70b9\u96fb\u8377\u306e\u5834\u5408\u306f\u91cd\u306d\u5408\u308f\u305b\u306e\u539f\u7406\u304b\u3089<\/p>\n

$$\\boldsymbol{E} = \\sum_i \\frac{q_i}{4\\pi \\varepsilon_0} \\frac{ \\boldsymbol{r}\u00a0 -\\boldsymbol{r}_i}{|\\boldsymbol{r}\u00a0 -\\boldsymbol{r}_i|^3} $$\"\"<\/p>\n

\u96fb\u6c17\u53cc\u6975\u5b50\u306b\u3088\u308b\u96fb\u5834<\/a><\/h4>\n

\u96fb\u6c17\u53cc\u6975\u5b50\u3068\u306f\u6b63\u96fb\u8377 $q$ \u3068\u8ca0\u96fb\u8377 $-q$ \u304c\u5fae\u5c0f\u8ddd\u96e2 $\\boldsymbol{d}$ \u3067\u5bfe\u306b\u306a\u3063\u3066\u3044\u308b\u72b6\u614b\u3002\u96fb\u6c17\u53cc\u6975\u30e2\u30fc\u30e1\u30f3\u30c8 $\\boldsymbol{p} \\equiv q \\boldsymbol{d}$ \u306b\u3088\u308b\u9060\u65b9\u306e\u96fb\u5834\u306f<\/p>\n

$$\\boldsymbol{E}= \\frac{1}{4\\pi\\varepsilon_0}\\left\\{ 3 \\frac{\\boldsymbol{r}\\cdot \\boldsymbol{p} }{r^5} \\boldsymbol{r} -\\frac{\\boldsymbol{p}}{r^3}\\right\\}$$\"\"<\/p>\n

\u8ef8\u5bfe\u79f0\u306a\u96fb\u8377\u5206\u5e03\u306b\u3088\u308b\u96fb\u5834<\/a><\/h4>\n

$z$ \u8ef8\u306b\u3064\u3044\u3066\u8ef8\u5bfe\u79f0\u306a\u96fb\u8377\u5206\u5e03\u3092\u8868\u3059\u96fb\u8377\u5bc6\u5ea6\u306f<\/p>\n

$$\\rho(\\boldsymbol{r}) = \\rho(\\varrho), \\quad\\boldsymbol{\\varrho}\\equiv (x, y, 0), \\ \\\u00a0 \\varrho\\equiv \\sqrt{x^2+y^2}$$<\/p>\n

\u96fb\u5834\u306f<\/p>\n

$$\\boldsymbol{E} = \\frac{Q_{\\varrho}}{2\\pi \\varepsilon_0} \\frac{\\boldsymbol{\\varrho}}{{\\varrho}^2}$$<\/p>\n

\u3053\u3053\u3067 $Q_{\\varrho}$ \u306f\uff0c$z$ \u8ef8\u3092\u4e2d\u5fc3\u3068\u3057\uff0c\u5e95\u9762\u7a4d\u304c $\\pi \\varrho^2$ \u306e\u5358\u4f4d\u9ad8\u3055\u306e\u5186\u67f1\u5185\u306e\u5168\u96fb\u8377\u3067\u3042\u308b\u3002\u7279\u306b $z$ \u8ef8\u4e0a\u306e\u4e00\u69d8\u306a\u7dda\u96fb\u8377\u5bc6\u5ea6 $\\lambda$ \u306e\u5834\u5408<\/a>\u306f\uff0c$Q_{\\varrho} \\rightarrow \\lambda$ \u3068\u3059\u308c\u3070\u3088\u3044\u3002\"\"<\/p>\n

\u9762\u5bfe\u79f0\u306a\u96fb\u8377\u5206\u5e03\u306b\u3088\u308b\u96fb\u5834<\/a><\/h4>\n

$x = 0$ \u306e $yz$ \u5e73\u9762\u306b\u3064\u3044\u3066\u9762\u5bfe\u79f0\u306a\u96fb\u8377\u5206\u5e03\u3092\u8868\u3059\u96fb\u8377\u5bc6\u5ea6\u306f<\/p>\n

$$\\rho(\\boldsymbol{r}) = \\rho(|x|)$$<\/p>\n

\u96fb\u5834\u306f<\/p>\n

$$ E_x = \\frac{Q_{|x|}}{2 \\epsilon_0} \\frac{x}{|x|}, \\quad E_y = E_z = 0$$<\/p>\n

$Q_{|x|}$ \u306f $yz$ \u9762\u304c\u5358\u4f4d\u9762\u7a4d\uff0c$x$ \u65b9\u5411\u304c $-x$ \u304b\u3089 $x$ \u307e\u3067\u306e\u76f4\u65b9\u4f53\u5185\u306e\u5168\u96fb\u8377\u3002\u7279\u306b\uff0c$yz$ \u9762\u4e0a\u306e\u4e00\u69d8\u9762\u96fb\u8377\u5bc6\u5ea6 $\\sigma$ \u306e\u5834\u5408<\/a>\u306f\uff0c$Q_{|x|} \\rightarrow \\sigma$ \u3068\u3059\u308c\u3070\u3088\u3044\u3002\"\"<\/p>\n

\u7403\u5bfe\u79f0\u306a\u96fb\u8377\u5206\u5e03\u306b\u3088\u308b\u96fb\u5834<\/a><\/h4>\n

\u539f\u70b9\u3092\u4e2d\u5fc3\u3068\u3057\u305f\u7403\u5bfe\u79f0\u306a\u96fb\u8377\u5206\u5e03\u3092\u8868\u3059\u96fb\u8377\u5bc6\u5ea6\u306f<\/p>\n

$$\\rho(\\boldsymbol{r}) = \\rho(r), \\quad r \\equiv \\sqrt{x^2 + y^2 + z^2}$$<\/p>\n

\u96fb\u5834\u306f<\/p>\n

$$\\boldsymbol{E} = \\frac{Q_r}{4\\pi \\varepsilon_0} \\frac{\\boldsymbol{r}}{r^3}$$<\/p>\n

$Q_r$ \u306f\u539f\u70b9\u3092\u4e2d\u5fc3\u3068\u3059\u308b\u534a\u5f84 $r$ \u306e\u7403\u5185\u306e\u5168\u96fb\u8377\u3002\u7403\u5bfe\u79f0\u306a\u96fb\u8377\u5206\u5e03\u306e\u5834\u5408\u306f\uff0c\u3053\u306e $Q_r$ \u3092\u3082\u3064\u70b9\u96fb\u8377\u3092\u539f\u70b9\u306b\u304a\u3044\u305f\u3068\u304d\u306e\u96fb\u5834\u3068\u7b49\u4fa1\u3067\u3042\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u306e\u3067\u3042\u3063\u305f\u3002<\/p>\n

\u96fb\u6d41\u5bc6\u5ea6\u304b\u3089\u76f4\u63a5\u9759\u78c1\u5834\u3092\u6c42\u3081\u308b\u5f0f\uff1a\u30d3\u30aa – \u30b5\u30d0\u30fc\u30eb\u306e\u6cd5\u5247<\/a><\/h3>\n

\\begin{eqnarray}
\n\\boldsymbol{B} (\\boldsymbol{r}) = \\nabla\\times \\boldsymbol{A} (\\boldsymbol{r})&=& \\frac{1}{4\\pi \\varepsilon_0 c^2} \\iiint \\frac{\\boldsymbol{J}(\\boldsymbol{r}’)\\times (\\boldsymbol{r} -\\boldsymbol{r}’)}{|\\boldsymbol{r} -\\boldsymbol{r}’|^3} \\,dV’
\n\\end{eqnarray}<\/p>\n

\u3053\u306e\u7a4d\u5206\u304c\uff08\u6bd4\u8f03\u7684\uff09\u7c21\u5358\u306b\u3067\u304d\u308b\u3044\u304f\u3064\u304b\u306e\u4f8b\u3092\u4ee5\u4e0b\u306b\u307e\u3068\u3081\u308b\u3002<\/p>\n

\u76f4\u7dda\u96fb\u6d41\u306b\u3088\u308b\u78c1\u5834<\/a><\/h4>\n

$z$ \u8ef8\u4e0a\u306e\u76f4\u7dda\u96fb\u6d41 $\\boldsymbol{I} = (0, 0, I)$ \u3092\u8868\u3059\u96fb\u6d41\u5bc6\u5ea6 $\\boldsymbol{J}$ \u306f\u30c7\u30a3\u30e9\u30c3\u30af\u306e\u30c7\u30eb\u30bf\u95a2\u6570\u3092\u4f7f\u3063\u3066<\/p>\n

$$\\boldsymbol{J} = (0, 0, J_z) = \\boldsymbol{I}\\delta(x) \\delta(y)$$<\/p>\n

\u78c1\u5834\u306f<\/p>\n

$$\\begin{eqnarray}
\n\\boldsymbol{B} &=& \\frac{1}{2\\pi \\varepsilon_0 c^2}\u00a0 \\frac{\\boldsymbol{I}\\times\\boldsymbol{\\varrho}}{\\varrho^2}
\n\\end{eqnarray}, \\quad \\boldsymbol{\\varrho} = (x, y, 0), \\ \\varrho = \\sqrt{x^2+y^2}$$\"\"<\/p>\n

 <\/p>\n

\u5186\u96fb\u6d41\u306b\u3088\u308b\u78c1\u5834<\/a><\/h4>\n

$xy$ \u5e73\u9762\u4e0a\u306e\u539f\u70b9\u3092\u4e2d\u5fc3\u3068\u3057\u305f\u534a\u5f84 $a$ \u306e\u5186\u5468\u4e0a\u3092\u6d41\u308c\u308b\u96fb\u6d41 $I$ \u3092\u8868\u3059\u96fb\u6d41\u5bc6\u5ea6\u306f<\/p>\n

\\begin{eqnarray}
\n\\boldsymbol{J} &=& (J_x, J_y, 0) \\\\
\n&=& (-I \\sin\\phi , I \\cos\\phi , 0)\\times \\delta(\\varrho-a) \\,\\delta(z)
\n\\end{eqnarray}<\/p>\n

\u30d3\u30aa\u30fb\u30b5\u30d0\u30fc\u30eb\u306e\u6cd5\u5247\u306b\u5165\u308c\u3066\u78c1\u5834\u3092\u6c42\u3081\u308b\u304c\uff0c\u4e00\u822c\u306b\u7a4d\u5206\u304c\u3067\u304d\u308b\u308f\u3051\u3067\u306f\u306a\u304f\uff0c\u3042\u3048\u3066\u66f8\u304f\u3068 $z$ \u8ef8\u4e0a $\\boldsymbol{r} = (0, 0, z)$ \u306e\u78c1\u5834\u306f\u7c21\u5358\u306b\u7a4d\u5206\u3067\u304d\u3066\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u306a\u308b\u3002<\/p>\n

\\begin{eqnarray}
\nB_x(0,0,z) &=& 0\\\\
\nB_y(0,0,z)&=& 0 \\\\
\nB_z(0,0,z) &=& \\frac{I a^2}{2 \\varepsilon_0 c^2\\left\\{z^2 + a^2\\right\\}^{\\frac{3}{2}}}
\n\\end{eqnarray}<\/p>\n

\"\"<\/p>\n

\u5fae\u5c0f\u306a\u5186\u96fb\u6d41\u30fb\u78c1\u6c17\u53cc\u6975\u5b50\u306b\u3088\u308b\u78c1\u5834<\/a><\/h4>\n

\u5fae\u5c0f\u306a\u5186\u96fb\u6d41\u304c\u3064\u304f\u308b\u9060\u65b9\u306e\u78c1\u5834\u306f<\/p>\n

$$a^2 \\ll r^2 = x^2 + y^2 + z^2$$<\/p>\n

\u3068\u3059\u308b\u3068\uff0c\u78c1\u6c17\u53cc\u6975\u30e2\u30fc\u30e1\u30f3\u30c8 $\\boldsymbol{\\mu} \\equiv (0, 0, I\\pi a^2)$ \u3092\u6301\u3064\u78c1\u6c17\u53cc\u6975\u5b50\u304c\u3064\u304f\u308b\u78c1\u5834\u3068\u306a\u308a\uff0c<\/p>\n

$$\\boldsymbol{B} = \\frac{1}{4\\pi\\varepsilon_0 c^2} \\left\\{3 \\frac{\\boldsymbol{r}\\cdot\\boldsymbol{\\mu} }{r^5} \\boldsymbol{r} -\\frac{\\boldsymbol{\\mu}}{r^3} \\right\\}$$<\/p>\n

\"\"<\/p>\n

\u30bd\u30ec\u30ce\u30a4\u30c9\u3092\u6d41\u308c\u308b\u96fb\u6d41\u306b\u3088\u308b\u78c1\u5834<\/a><\/h4>\n

$z$ \u8ef8\u3092\u4e2d\u5fc3\u3068\u3057\uff0c\u534a\u5f84 $a$ \u3067 $z$ \u65b9\u5411\u306b\u5358\u4f4d\u9577\u3055\u3042\u305f\u308a $n$ \u56de\u5dfb\u304d\u306e\u5341\u5206\u306b\u9577\u3044\u30bd\u30ec\u30ce\u30a4\u30c9\u3092\u96fb\u6d41 $I$ \u304c\u6d41\u308c\u308b\u3002\u3053\u308c\u3092\u8868\u3059\u96fb\u6d41\u5bc6\u5ea6\u306f\uff08\u307b\u3093\u3068\u306f\u87ba\u65cb\u72b6\u306b\u5dfb\u3044\u3066\u3042\u308b\u3068\u3053\u308d\u3092\uff0c\u5186\u96fb\u6d41\u3092$z$ \u65b9\u5411\u306b\u5358\u4f4d\u9577\u3055\u3042\u305f\u308a $n$ \u500b\u91cd\u306d\u3066\u8868\u3059\u3053\u3068\u306b\u3057\u3066\uff09<\/p>\n

\\begin{eqnarray}
\n\\boldsymbol{J} &=& (J_x, J_y, 0) \\\\
\n&=& (-n I \\sin\\phi , n I \\cos\\phi , 0)\\times \\delta(\\sqrt{x^2 + y^2}-a)
\n\\end{eqnarray}<\/p>\n

\u78c1\u5834\u306f<\/p>\n

$$B_x = B_y = 0, \\quad
\nB_z =\\left\\{\\begin{array}{ll}\\frac{n I}{\\varepsilon_0 c^2}\u00a0 & (\\sqrt{x^2 + y^2}< a)\\\\ \\ \\\\0 & (\\sqrt{x^2 + y^2}>a)\\end{array}\\right.$$<\/p>\n

\u30bd\u30ec\u30ce\u30a4\u30c9\u306e\u5916\u90e8 $\\sqrt{x^2 + y^2}>a$ \u3067\u306f $B_z$\u00a0 \u3082\u542b\u3081\u3066 $\\boldsymbol{B} = \\boldsymbol{0}$\uff0c\u30bd\u30ec\u30ce\u30a4\u30c9\u306e\u5185\u90e8 $\\sqrt{x^2 + y^2}<a$ \u3067\u306f\uff0c\u30bd\u30ec\u30ce\u30a4\u30c9\u306b\u6cbf\u3063\u3066\u4e00\u5b9a\u306e\u5927\u304d\u3055\u306e $B_z$ \u306e\u307f\u304c\u5b58\u5728\u3059\u308b\u3002<\/p>\n

\"\"<\/p>\n","protected":false},"excerpt":{"rendered":"

\u3053\u308c\u307e\u3067\u306e\u3068\u3053\u308d\u3092\u307e\u3068\u3081\u3066\u304a\u304f\u3002<\/p>

\u7d9a\u304d\u3092\u8aad\u3080<\/a><\/p>\n","protected":false},"author":33,"featured_media":0,"parent":2561,"menu_order":30,"comment_status":"closed","ping_status":"closed","template":"","meta":{"inline_featured_image":false,"footnotes":""},"class_list":["post-2751","page","type-page","status-publish","hentry","nodate","item-wrap"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/pages\/2751","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/users\/33"}],"replies":[{"embeddable":true,"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/comments?post=2751"}],"version-history":[{"count":24,"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/pages\/2751\/revisions"}],"predecessor-version":[{"id":10650,"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/pages\/2751\/revisions\/10650"}],"up":[{"embeddable":true,"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/pages\/2561"}],"wp:attachment":[{"href":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/wp-json\/wp\/v2\/media?parent=2751"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}