ãã®èšäºã§ã¯ãéç£çã«ã€ããŠåºæ¬çãªå
容ã説æããåŸãéç£çã®ç¹åŸŽãšéç£çã®é¢é£çšèª(æ¯éç£çã»åéç£çã»æ倧éç£ç)ãªã©ãã€ããŠè©³ãã説æããŸãã
éç£çãšã¯
éç£ç(ãšãããã€)ãšã¯ç©è³ªã®ç£æã®éãããã(ç£åã®ãããã)ã®ããšæå³ããŸãã
ç©è³ªãç£çã®äžã«çœ®ããšãç©è³ªã¯ç£æ°ã垯ã³ãŠç£ç³ãšåããããªæ§è³ªãšãªããŸã(äžå³ã®å ŽåãAåŽãS極ã§BåŽãN極ã®ç£ç³ã®ãããªæãã§ã)ããã®ãšããç£çã®åŒ·ãH[A/m]ã倧ãããããšãç©è³ªäžã®ç£æå¯åºŠB[T](ç£ç³ãšããŠã®åŒ·ããè¡šã)ãæ¯äŸããŠå€§ãããªããŸãããã®æã®å€åçã®ããšãéç£çÎŒãšãããŸãã
ç£çã®åŒ·ãH[A/m]ãç©è³ªäžã®ç£æå¯åºŠB[T]ãéç£çÎŒã®é¢ä¿ãåŒã§è¡šããšã
\begin{eqnarray}
B={\mu}H
\end{eqnarray}
ãšãªããŸãããã®éç£çÎŒã®åäœã¯[H/m](ãã³ãªãŒæ¯ã¡ãŒãã«)ãŸãã¯[N/A2](ãã¥ãŒãã³æ¯å¹³æ¹ã¢ã³ãã¢)ãšãªããŸãããªããäžè¬çã«ã¯ããã®åŸã«èª¬æããæ¯éç£çÎŒrã®æ¹ãéç£çÎŒããå€ãçšããããŠããŸãã
ãã®æãç£çã®åŒ·ãH[A/m]ãåãã®å Žåãéç£çÎŒã倧ãã(ç£æãéãããã)ã»ã©ãç©è³ªäžã®ç£æå¯åºŠB[T]ã倧ãããªããŸããããªãã¡ãéç£çÎŒã倧ããã»ã©ãç©è³ªäžãéãç£æãå¢ããŠç£ç³ãšããŠã®åŒ·ããå¢ããšããããšã«ãªããŸãã
æ¯éç£çãšã¯
æ¯éç£çÎŒrãšã¯ãç空ã®éç£çÎŒ0(=4ÏÃ10-7[H/m])ãåºæºã®â1âãšããŠãçžå¯Ÿçã«ç©è³ªã®éç£çãè¡šãããã®ã§ããããªãã¡ãåŒã§æžããšãç©è³ªã®éç£çÎŒãšç空ã®éç£çÎŒ0ãšã®æ¯ã§ããã以äžã®åŒã§è¡šãããŸãã
\begin{eqnarray}
{\mu}_r=\frac{{\mu}}{{\mu}_0}
\end{eqnarray}
æšæãã¢ã«ãããŠã ã®ãããªç©è³ªã¯ç©è³ªäžã«ç£æãã»ãšãã©éããªããããç£ç³ãšããŠã®æ§è³ªããªããæ¯éç£çÎŒrã¯ã»ãŒ1ãšãªããŸããäžæ¹ãéãªã©ã®ç£ç³ã«ãã£ã€ãç©è³ªã¯ç©è³ªäžã«ç£æãéãããããç£ç³ãšããŠã®æ§è³ªããããæ¯éç£çÎŒrã¯5000çšåºŠãšãªããŸãããªããæ¯éç£çÎŒrã¯"æ¯"éç£çãªã®ã§åäœã¯ãããŸããã
è£è¶³
- éç£çã¯è±èªã§ã¯ãMagnetic PermeabilityããšãããŸãã
- éç£çã¯ç£æå¯åºŠB[T]ãšç£çã®åŒ·ãH[A/m]ã®é¢ä¿ãè¡šãB-Hã«ãŒã(ç£åæ²ç·)ã®åŸãã«ãªããŸã(ãã®èšäºã®åŸåã«è©³ãã説æããŠããŸã)ã
- æ¯éç£çÎŒrã®å€§ããã«ãã£ãŠåžžç£æ§äœã匷ç£æ§äœãåç£æ§äœã«åé¡ãããŸãã
- å ·äœçã«ã¯éã®æ¯éç£çÎŒrã¯120ïœ20000çšåºŠãšç¶æ ã«ãã£ãŠå€ãããŸãã
ãéç£çã®ç¹åŸŽãç£çã®åŒ·ã(âé»æµã®å€§ãã)ã«ãã£ãŠå€åããŸã
å
ã»ã©ãç£çã®åŒ·ãH[A/m]ãšç£æå¯åºŠB[T]ã¯æ¯äŸé¢ä¿ã«ãããéç£çÎŒãçšãããš
\begin{eqnarray}
B={\mu}H
\end{eqnarray}
ã®é¢ä¿åŒãæãç«ã€ããšã説æããŸãããã€ãŸããç£æå¯åºŠB[T]ãšç£çã®åŒ·ãH[A/m]ã®é¢ä¿ãè¡šãB-Hã«ãŒã(ç£åæ²ç·)ã¯äžå³ã®éè²ã®çŽç·ãšãªãããã®éè²ã®ç·ã®åŸããéç£çÎŒãšãªããŸããéè²ã®çŽç·ã¯åŸããå€ãããªããããéç£çÎŒã¯äžå®ãšããããšã«ãªããŸãã
ããããå®éã®B-Hã«ãŒãã¯äžå³ã®èµ€è²ã®ç·ã®ããã«ãªããéç£çÎŒã¯äžå®ã§ã¯ãªããç£çã®åŒ·ãH[A/m]ã«ãã£ãŠãéç£çÎŒã倧ããå€åããŸã(B-Hã«ãŒãã®åŸããå€ãã£ãŠããã®ã¯éç£çÎŒãå€åããŠããããã§ã)ããŸããç£çã®åŒ·ãH[A/m]ã¯é»æµã®å€§ããã«æ¯äŸãããããé»æµã®å€§ããã«ãã£ãŠãéç£çÎŒã倧ããå€åãããšããããšã«ããªããŸãã
åéç£çÎŒiãšæ倧éç£çÎŒmã«ã€ããŠ
éç£çÎŒã«ã¯åéç£çÎŒiãšæ倧éç£çÎŒmãšããçšèªããããŸãã
äžå³ã¯ç£æå¯åºŠB[T]ãšç£çã®åŒ·ãH[A/m]ã®é¢ä¿ãè¡šãB-Hã«ãŒã(ç£åæ²ç·)ãšãéç£çÎŒãšç£çã®åŒ·ãH[A/m]ã®é¢ä¿ãè¡šãÎŒ-Hã«ãŒã(ÎŒæ²ç·)ã§ããÎŒ-Hã«ãŒã(ÎŒæ²ç·)ã¯B-Hã«ãŒã(ç£åæ²ç·)ã®åŸã(Ξ)ã®å€§ããã瀺ããŠããŸãã
ãã®B-Hã«ãŒã(ç£åæ²ç·)ãšÎŒ-Hã«ãŒã(ÎŒæ²ç·)ã«ãããŠãåéç£çÎŒiãšæ倧éç£çÎŒmã¯ä»¥äžã®ç®æã瀺ããŠããŸãã
- åéç£çÎŒi
- æ倧éç£çÎŒm
ç£çã®åŒ·ãH[A/m]ã0ã®æã«ãããéç£çÎŒã§ããäžè¬çã«éç£çãšåŒã°ããã®ã¯ããã®åéç£çÎŒ0ã®ããšã§ããããã§ã©ã€ãæãªã©ã®ããŒã¿ã·ãŒãã«èŒã£ãŠããã®ãåéç£çÎŒiã®å€ãšãªã£ãŠããŸãã
B-Hã«ãŒã(ç£åæ²ç·)ã«ãããéç£çÎŒã®æ倧å€ã§ããæ倧éç£çÎŒmãè¶ ãããšãéç£çÎŒã¯åŸã ã«æžå°ããŠãããŸãã
è£è¶³
éç£çÎŒãšèªé»çεã¯äŒŒãŠããŸã
éç£çÎŒãšã¯ç©è³ªã®ç£æã®éãããã(ç£åã®ãããã)ã®ããšæå³ããŸããäžæ¹ãèªé»çεãšã¯ç©è³ªã®èªé»å極ã®ããããã®ããšæå³ããŸãã
ãã®éç£çÎŒãšèªé»çεã¯ãšãŠã䌌ãŠããé¢ä¿ãªã®ã§ãã
éç£çÎŒã«ã¯ç空ã®éç£çÎŒ0(=4ÏÃ10-7[H/m])ãåºæºã®â1âãšããŠãçžå¯Ÿçã«ç©è³ªã®éç£çãè¡šããæ¯èªé»çÎŒrãããããšã説æããŸãããäžæ¹ãèªé»çã«ã¯ç空ã®èªé»çε0 (=8.85Ã10-12[F/m])ãåºæºã®â1âãšããŠãçžå¯Ÿçã«ç©è³ªã®èªé»çãè¡šããæ¯èªé»çε0ããããŸããéç£çãšèªé»çãæŽçãããšäžè¡šã®ããã«ãªããŸãã
ãŸãšã
ãã®èšäºã§ã¯ãéç£çãã«ã€ããŠã以äžã®å
容ã説æããŸããã
åœèšäºã®ãŸãšã
- éç£çãšã¯
- æ¯éç£çãšã¯
- éç£çã¯ç£çã®åŒ·ã(âé»æµã®å€§ãã)ã«ãã£ãŠå€åããããš
- åéç£çãšæ倧éç£çã«ã€ããŠ
- éç£çãšèªé»çã«ã€ããŠ
ãèªã¿é ãããããšãããããŸããã
åœãµã€ãã§ã¯é»æ°ã«é¢ããæ§ã
ãªæ
å ±ãèšèŒããŠããŸããåœãµã€ãã®å
šèšäºäžèŠ§ã«ã¯ä»¥äžã®ãã¿ã³ãã移åããããšãã§ããŸãã