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Helmholtz coil

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twice the frequency requires twice the voltage across the coil. Instead of directly driving the coil with a high voltage, a series resonant circuit may be used to provide the high voltage. A series capacitor is added in series with the coils. The capacitance is chosen to resonate the coil at the desired frequency. Only the coils parasitic resistance remains. This method only works at frequencies close to the resonant frequency; to generate the field at other frequencies requires different capacitors. The Helmholtz coil resonant frequency,
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field and living tissue). The required magnetic fields are usually either pulse or continuous sinewave. The magnetic field frequency range can be anywhere from near DC (0 Hz) to many kilohertz or even megahertz (MHz). An AC Helmholtz coil driver is needed to generate the required time-varying magnetic field. The waveform amplifier driver must be able to output high AC current to produce the magnetic field.
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Generating a static magnetic field is relatively easy; the strength of the field is proportional to the current. Generating a high-frequency magnetic field is more challenging. The coils are inductors, and their impedance increases proportionally with frequency. To provide the same field intensity at
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Most Helmholtz coils use DC (direct) current to produce a static magnetic field. Many applications and experiments require a time-varying magnetic field. These applications include magnetic field susceptibility tests, scientific experiments, and biomedical studies (the interaction between magnetic
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When a Helmholtz pair of coils carry an equal electric current in the opposite direction, they create a region of nearly uniform magnetic field gradient. This is known as anti-Helmholtz coil, and is used for creating magnetic traps for atomic physics experiments.
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on the same axis, carrying an equal electric current in the same direction. Besides creating magnetic fields, Helmholtz coils are also used in scientific apparatus to cancel external magnetic fields, such as the Earth's magnetic field.
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has the same structure as Helmholtz coils, but with the magnets separated further apart so that the field expands in the middle, trapping charged particles with the diverging field lines. If one coil is reversed, it produces a
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Magnetic field lines in a plane bisecting the current loops. Note the field is approximately uniform in between the coil pair. (In this picture the coils are placed one beside the other: the axis is horizontal.)
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Contours showing the magnitude of the magnetic field near a coil pair, with one coil at top and the other at bottom. Inside the central "octopus", the field is within 1% of its central value
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A Helmholtz pair consists of two identical circular magnetic coils that are placed symmetrically along a common axis, one on each side of the experimental area, and separated by a distance
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reduces the difference in field between the center and the planes of the coils, at the expense of worsening the field's uniformity in the region near the center, as measured by
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showed in 1873 that a third larger-diameter coil located midway between the two Helmholtz coils with the coil distance increased from coil radius
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as explained below), but leaves about 7% variation in field strength between the center and the planes of the coils. A slightly larger value of
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When the pair of two electromagnets of a Helmholtz coil carry an equal electric current in the opposite direction, it is known as
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on three perpendicular axes used to cancel the Earth's magnetic field inside the vacuum tank in a 1957 electron beam experiment
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can reduce the variance of the field on the axis to zero up to the sixth derivative of position. This is sometimes called a
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Using a function generator and a high-current waveform amplifier driver to generate high-frequency Helmholtz magnetic field
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electromagnetic composite testing laboratory in 1993, for testing of composite materials to low-frequency magnetic fields.
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To improve the uniformity of the field in the space inside the coils, additional coils can be added around the outside.
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The calculation of the exact magnetic field at any point in space is mathematically complex and involves the study of
3942: 170: 759: 292: 224: 3286:{\displaystyle 4\pi \times 10^{-7}{\text{ T}}\cdot {\text{m/A}}=1.257\times 10^{-6}{\text{ T}}\cdot {\text{m/A}},} 1115:{\displaystyle 4\pi \times 10^{-7}{\text{ T}}\cdot {\text{m/A}}=1.257\times 10^{-6}{\text{ T}}\cdot {\text{m/A}},} 4228: 627:
The calculation detailed below gives the exact value of the magnetic field at the center point. If the radius is
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Use the above equation in the mathematics section to calculate the coil current for a desired magnetic field,
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Start with the formula for the on-axis field due to a single wire loop which is itself derived from the
75: 55: 1436: 1201: 987:{\displaystyle B_{1}(x)={\frac {\mu _{0}IR^{2}}{2(R^{2}+x^{2})^{3/2}}}=\xi (x){\frac {\mu _{0}I}{2R}}.} 4196: 4005: 826: 3812: 3838: 3344: 3985: 4071: 1003: 81: 1651: 590: 4161: 3965: 3923: 3179: 734: 451:. Things are simpler along the axis of the coil-pair, and it is convenient to think about the 2717: 2046: 1410: 502: 364: 135: 3574: 535: 508: 356: 4203: 4111: 3949: 3886: 448: 4145: 3320: 3297: 1178: 1155: 1128: 562: 478: 144: 17: 4177: 3818: 3158:{\displaystyle I=\left({\frac {5}{4}}\right)^{3/2}\left({\frac {BR}{\mu _{0}n}}\right)} 2363: 1692: 458: 272: 117: 97: 51: 559:. The inflection point for a simple coil is located along the coil axis at a distance 4217: 3993: 3880: 2070: 1524: 505:
for the field strength due to each coil separately, one can guarantee that the order
452: 59: 3891: 3863: 3806: 3778:{\displaystyle C={\frac {1}{\left(2\pi f_{0}\right)^{2}\left(L_{1}+L_{2}\right)}}} 4090: 639:, then the magnetic field B at the midpoint between the coils will be given by 4208: 4165: 85:
A beam of cathode rays in a vacuum tube bent into a circle by a Helmholtz coil
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term is also zero, and hence the leading non-constant term is of order
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Magnetic field induction along the axis crossing the center of coils;
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Then calculate the required Helmholtz coil driver amplifier voltage:
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Two circular coil device which creates a homogeneous magnetic field
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In some applications, a Helmholtz coil is used to cancel out the
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The points near the center (halfway between the two coils) have
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The points near the center (halfway between the two coils) have
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turns of wire, so the equivalent current in a one-turn coil is
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from its centre. Thus the locations for the two coils are
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The Calculation and Measurement of Helmholtz Coil Fields
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In an anti-Helmholtz pair, the B-field strength at any
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DeTroye, David J.; Chase, Ronald J. (November 1994),
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is the distance dependent, dimensionless coefficient.
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is a device for producing a region of nearly uniform
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Calculation of Magnetic Field inside Plasma Chamber
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are the inductances of the two Helmholtz coils, and
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Each coil carries an equal 37: 4185:, Army Research Laboratory, ARL-TN-35, 3910: 2805:{\displaystyle \xi (x-R/2)-\xi (x+R/2)} 2138:{\displaystyle \xi (x-R/2)+\xi (x+R/2)} 4107: 4096: 631:, the number of turns in each coil is 3894:, which also traps charged particles. 3561:are the resistances of the two coils. 3203:is the permeability of free space or 635:and the current through the coils is 7: 4017: 4015: 4192:from the original on April 18, 2013 3341:n = number of turns in each coil. 54:, named after the German physicist 4151:The Wolfram Demonstrations Project 4006:"Magnetic Field of a Current Loop" 314: 297: 246: 229: 192: 175: 25: 4168:to compute off-axis fields, from 1516:{\displaystyle \xi (x)=^{-3/2}\;} 1278:{\displaystyle \xi (x)=^{-3/2}\;} 1289:The Helmholtz coils consists of 78:for atomic physics experiments. 42:Helmholtz coil schematic drawing 4072:"ログイン - ASACUSA MUSASHI group" 3566:High-frequency series resonant 3044: 3035: 3020: 3017: 2998: 2983: 2974: 2960: 2951: 2942: 2927: 2924: 2903: 2890: 2881: 2866: 2852: 2839: 2836: 2822: 2799: 2779: 2770: 2750: 2672: 2662: 2633: 2624: 2601: 2591: 2562: 2553: 2500: 2480: 2471: 2451: 2403: 2397: 2343: 2334: 2319: 2316: 2297: 2282: 2267: 2258: 2243: 2240: 2219: 2206: 2197: 2182: 2168: 2155: 2132: 2112: 2103: 2083: 2001: 1991: 1962: 1953: 1930: 1920: 1891: 1882: 1829: 1809: 1800: 1780: 1732: 1726: 1629: 1620: 1605: 1602: 1583: 1568: 1546: 1540: 1492: 1488: 1479: 1464: 1455: 1449: 1443: 1358: 1352: 1343: 1337: 1254: 1244: 1229: 1220: 1214: 1208: 951: 945: 919: 892: 855: 849: 1: 3855:{\displaystyle {\sqrt {3}}R} 3511:is the angular frequency or 3315:= coil current, in amperes, 3943:Helmholtz Coil in CGS units 3062:Time-varying magnetic field 2740:, and the Taylor series of 1433:, the distance coefficient 74:, and is used for creating 4250: 3899:Army Research Laboratory's 3804: 3338:= coil radius, in meters, 3071:Driver voltage and current 1021:{\displaystyle \mu _{0}\;} 760:permeability of free space 1678:{\displaystyle x=\pm R/2} 1305:-turn coil. Substituting 1173:= coil radius, in meters, 617:{\displaystyle x=\pm R/2} 18:Quadrupole magnetic field 4197:Magnetic Fields of Coils 4052:www.accelinstruments.com 3918:Ramsden, Edward (2006). 3196:{\displaystyle \mu _{0}} 751:{\displaystyle \mu _{0}} 3948:March 24, 2012, at the 138:in the same direction. 4106:Cite journal requires 3988:by Richard Wotiz 2004 3856: 3829: 3802: 3779: 3680: 3592: 3487: 3349: 3332: 3309: 3287: 3197: 3159: 3059: 3051: 2806: 2734: 2733:{\displaystyle x\ll R} 2705: 2374: 2358: 2350: 2139: 2063: 2062:{\displaystyle x\ll R} 2034: 1703: 1679: 1646: 1639: 1517: 1427: 1426:{\displaystyle x\ll R} 1398: 1279: 1190: 1167: 1140: 1116: 1022: 988: 809: 752: 722: 618: 581: 553: 526: 495: 469: 444: 373: 361: 346:Earth's magnetic field 331: 283: 263: 215: 161: 128: 108: 86: 43: 35: 4234:Hermann von Helmholtz 4224:Electromagnetic coils 4146:Helmholtz-Coil Fields 3857: 3830: 3796: 3780: 3681: 3593: 3591:{\displaystyle f_{0}} 3488: 3347: 3333: 3310: 3288: 3198: 3160: 3052: 2814: 2807: 2735: 2706: 2375: 2351: 2147: 2140: 2064: 2035: 1704: 1680: 1640: 1529: 1518: 1428: 1399: 1280: 1191: 1168: 1141: 1117: 1030:permeability constant 1023: 989: 810: 753: 723: 619: 582: 554: 552:{\displaystyle x^{4}} 527: 525:{\displaystyle x^{2}} 496: 470: 379: 367: 359: 332: 284: 264: 216: 162: 129: 109: 84: 58:. It consists of two 56:Hermann von Helmholtz 41: 33: 3839: 3819: 3691: 3605: 3575: 3505:is the peak current, 3359: 3321: 3298: 3207: 3180: 3078: 2819: 2744: 2718: 2387: 2364: 2152: 2077: 2047: 1716: 1693: 1652: 1534: 1437: 1411: 1324: 1202: 1179: 1156: 1129: 1036: 1004: 836: 767: 735: 646: 591: 563: 536: 509: 479: 459: 293: 273: 225: 171: 145: 118: 114:equal to the radius 98: 3813:James Clerk Maxwell 3331:{\displaystyle R\;} 3308:{\displaystyle I\;} 1523:can be expanded in 1189:{\displaystyle x\;} 1166:{\displaystyle R\;} 1146:= coil current, in 1139:{\displaystyle I\;} 580:{\displaystyle R/2} 494:{\displaystyle x=0} 160:{\displaystyle h=R} 68:anti-Helmholtz coil 4202:2015-04-30 at the 4162:elliptic integrals 4156:Kevin Kuns (2007) 3992:June 28, 2007, at 3962:"Electromagnetism" 3852: 3825: 3803: 3775: 3676: 3588: 3483: 3350: 3328: 3305: 3283: 3193: 3155: 3047: 2802: 2730: 2701: 2699: 2370: 2346: 2135: 2059: 2030: 2028: 1699: 1675: 1635: 1513: 1423: 1394: 1297:times the current 1275: 1186: 1163: 1136: 1112: 1018: 984: 805: 748: 718: 614: 577: 549: 522: 491: 465: 445: 374: 362: 327: 279: 259: 211: 157: 124: 104: 87: 44: 36: 3847: 3828:{\displaystyle R} 3773: 3674: 3671: 3481: 3278: 3270: 3243: 3235: 3149: 3100: 2901: 2850: 2546: 2441: 2373:{\displaystyle x} 2217: 2166: 1875: 1770: 1702:{\displaystyle x} 1566: 1389: 1107: 1099: 1072: 1064: 979: 937: 803: 795: 713: 669: 468:{\displaystyle x} 282:{\displaystyle h} 127:{\displaystyle R} 107:{\displaystyle h} 16:(Redirected from 4241: 4229:Magnetic devices 4193: 4191: 4184: 4149:by Franz Kraft, 4123: 4122: 4115: 4109: 4104: 4102: 4094: 4093:on June 2, 2018. 4089:. 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258: 257: 245: 237: 236: 220: 218: 217: 212: 204: 203: 191: 183: 182: 166: 164: 163: 158: 136:electric current 133: 131: 130: 125: 113: 111: 110: 105: 34:A Helmholtz coil 21: 4249: 4248: 4244: 4243: 4242: 4240: 4239: 4238: 4214: 4213: 4204:Wayback Machine 4189: 4182: 4175: 4131: 4126: 4116: 4105: 4095: 4084: 4083: 4079: 4070: 4069: 4065: 4056: 4054: 4046: 4045: 4041: 4032: 4030: 4021: 4020: 4013: 4004: 4003: 3999: 3984: 3980: 3971: 3969: 3960: 3959: 3955: 3950:Wayback Machine 3941: 3937: 3930: 3917: 3916: 3912: 3908: 3887:magnetic bottle 3872: 3837: 3836: 3817: 3816: 3809: 3791: 3757: 3744: 3743: 3739: 3718: 3711: 3707: 3706: 3705: 3689: 3688: 3653: 3640: 3639: 3635: 3626: 3608: 3603: 3602: 3578: 3573: 3572: 3568: 3559: 3553: 3550: 3544: 3539: 3533: 3530: 3524: 3512: 3508: 3500: 3467: 3457: 3444: 3420: 3403: 3390: 3357: 3356: 3319: 3318: 3296: 3295: 3254: 3219: 3205: 3204: 3183: 3178: 3177: 3168: 3135: 3134: 3126: 3120: 3088: 3087: 3076: 3075: 3073: 3064: 3034: 2997: 2941: 2880: 2817: 2816: 2742: 2741: 2716: 2715: 2698: 2697: 2671: 2661: 2600: 2590: 2552: 2548: 2538: 2521: 2520: 2509: 2508: 2447: 2443: 2433: 2416: 2415: 2406: 2385: 2384: 2362: 2361: 2333: 2296: 2257: 2196: 2150: 2149: 2075: 2074: 2045: 2044: 2027: 2026: 2000: 1990: 1929: 1919: 1881: 1877: 1867: 1850: 1849: 1838: 1837: 1776: 1772: 1762: 1745: 1744: 1735: 1714: 1713: 1691: 1690: 1650: 1649: 1619: 1582: 1532: 1531: 1491: 1478: 1435: 1434: 1409: 1408: 1381: 1364: 1363: 1327: 1322: 1321: 1253: 1243: 1200: 1199: 1177: 1176: 1154: 1153: 1127: 1126: 1083: 1048: 1034: 1033: 1007: 1002: 1001: 971: 957: 956: 918: 908: 895: 888: 877: 864: 863: 839: 834: 833: 827:Biot–Savart law 823: 779: 765: 764: 762: 738: 733: 732: 693: 692: 657: 655: 644: 643: 589: 588: 561: 560: 539: 534: 533: 512: 507: 506: 477: 476: 457: 456: 442: 436:, and 1.1  435: 428: 421: 414: 407: 400: 393: 386: 354: 317: 296: 291: 290: 271: 270: 249: 228: 223: 222: 195: 174: 169: 168: 143: 142: 116: 115: 96: 95: 92: 28: 23: 22: 15: 12: 11: 5: 4247: 4245: 4237: 4236: 4231: 4226: 4216: 4215: 4212: 4211: 4206: 4194: 4173: 4154: 4142: 4137: 4130: 4129:External links 4127: 4125: 4124: 4108:|journal= 4077: 4063: 4039: 4011: 3997: 3978: 3953: 3935: 3928: 3909: 3907: 3904: 3903: 3902: 3895: 3883: 3878: 3871: 3868: 3851: 3846: 3824: 3805:Main article: 3790: 3787: 3786: 3785: 3770: 3764: 3760: 3756: 3751: 3747: 3742: 3736: 3731: 3725: 3721: 3717: 3714: 3710: 3704: 3699: 3696: 3686: 3670: 3666: 3660: 3656: 3652: 3647: 3643: 3638: 3632: 3629: 3625: 3620: 3615: 3611: 3585: 3581: 3567: 3564: 3563: 3562: 3557: 3548: 3542: 3537: 3528: 3522: 3506: 3494: 3493: 3478: 3472: 3464: 3460: 3456: 3451: 3447: 3441: 3436: 3431: 3425: 3417: 3410: 3406: 3402: 3397: 3393: 3387: 3382: 3377: 3370: 3367: 3364: 3326: 3303: 3282: 3274: 3264: 3261: 3257: 3253: 3250: 3247: 3239: 3229: 3226: 3222: 3218: 3215: 3212: 3190: 3186: 3153: 3147: 3142: 3138: 3132: 3129: 3123: 3117: 3113: 3109: 3104: 3099: 3096: 3091: 3086: 3083: 3072: 3069: 3063: 3060: 3046: 3041: 3037: 3033: 3029: 3025: 3022: 3019: 3014: 3009: 3004: 3000: 2996: 2992: 2988: 2985: 2982: 2979: 2976: 2973: 2969: 2965: 2962: 2959: 2956: 2953: 2948: 2944: 2940: 2936: 2932: 2929: 2926: 2921: 2916: 2913: 2909: 2905: 2900: 2895: 2892: 2887: 2883: 2879: 2875: 2871: 2868: 2865: 2862: 2858: 2854: 2849: 2844: 2841: 2838: 2835: 2831: 2827: 2824: 2801: 2798: 2794: 2790: 2787: 2784: 2781: 2778: 2775: 2772: 2769: 2765: 2761: 2758: 2755: 2752: 2749: 2729: 2726: 2723: 2712: 2711: 2695: 2689: 2685: 2681: 2678: 2674: 2668: 2664: 2660: 2656: 2652: 2649: 2646: 2642: 2638: 2635: 2632: 2629: 2626: 2623: 2618: 2614: 2610: 2607: 2603: 2597: 2593: 2589: 2585: 2581: 2578: 2575: 2571: 2567: 2564: 2561: 2558: 2555: 2551: 2544: 2541: 2536: 2533: 2528: 2524: 2517: 2514: 2512: 2510: 2506: 2502: 2499: 2495: 2491: 2488: 2485: 2482: 2479: 2476: 2473: 2470: 2466: 2462: 2459: 2456: 2453: 2450: 2446: 2439: 2436: 2431: 2428: 2423: 2419: 2412: 2409: 2407: 2405: 2402: 2399: 2396: 2393: 2392: 2369: 2345: 2340: 2336: 2332: 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519: 515: 490: 487: 484: 464: 440: 433: 426: 419: 412: 405: 398: 391: 384: 353: 350: 324: 320: 316: 312: 308: 303: 299: 278: 256: 252: 248: 244: 240: 235: 231: 210: 207: 202: 198: 194: 190: 186: 181: 177: 156: 153: 150: 123: 103: 91: 88: 76:magnetic traps 60:electromagnets 52:magnetic field 48:Helmholtz coil 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4246: 4235: 4232: 4230: 4227: 4225: 4222: 4221: 4219: 4210: 4207: 4205: 4201: 4198: 4195: 4188: 4181: 4180: 4174: 4171: 4167: 4163: 4159: 4155: 4152: 4148: 4147: 4143: 4141: 4138: 4136: 4133: 4132: 4128: 4120: 4113: 4100: 4092: 4088: 4081: 4078: 4073: 4067: 4064: 4053: 4049: 4043: 4040: 4029: 4025: 4018: 4016: 4012: 4007: 4001: 3998: 3995: 3994:archive.today 3991: 3987: 3982: 3979: 3968:on 2011-06-03 3967: 3963: 3957: 3954: 3951: 3947: 3944: 3939: 3936: 3931: 3925: 3921: 3914: 3911: 3905: 3900: 3896: 3893: 3888: 3884: 3882: 3881:Halbach array 3879: 3877: 3874: 3873: 3869: 3867: 3865: 3849: 3844: 3822: 3814: 3808: 3800: 3795: 3789:Maxwell coils 3788: 3768: 3762: 3758: 3754: 3749: 3745: 3740: 3734: 3729: 3723: 3719: 3715: 3712: 3708: 3702: 3697: 3694: 3687: 3668: 3664: 3658: 3654: 3650: 3645: 3641: 3636: 3630: 3627: 3623: 3618: 3613: 3609: 3601: 3600: 3599: 3583: 3579: 3565: 3556: 3547: 3543: 3536: 3527: 3523: 3519: 3515: 3507: 3503: 3499: 3498: 3497: 3476: 3462: 3458: 3454: 3449: 3445: 3434: 3429: 3408: 3404: 3400: 3395: 3391: 3380: 3368: 3365: 3362: 3355: 3354: 3353: 3346: 3342: 3339: 3324: 3316: 3301: 3293: 3280: 3272: 3262: 3259: 3255: 3251: 3248: 3245: 3237: 3227: 3224: 3220: 3216: 3213: 3210: 3188: 3184: 3174: 3171: 3165: 3151: 3145: 3140: 3136: 3130: 3127: 3121: 3115: 3111: 3107: 3102: 3097: 3094: 3089: 3084: 3081: 3070: 3068: 3061: 3058: 3039: 3031: 3027: 3023: 3007: 3002: 2994: 2990: 2986: 2980: 2977: 2971: 2967: 2963: 2957: 2954: 2946: 2938: 2934: 2930: 2914: 2911: 2907: 2898: 2893: 2885: 2877: 2873: 2869: 2863: 2860: 2856: 2847: 2842: 2833: 2829: 2825: 2813: 2796: 2792: 2788: 2785: 2782: 2776: 2773: 2767: 2763: 2759: 2756: 2753: 2747: 2727: 2724: 2721: 2693: 2687: 2683: 2679: 2676: 2666: 2658: 2654: 2650: 2647: 2644: 2640: 2636: 2630: 2627: 2621: 2616: 2612: 2608: 2605: 2595: 2587: 2583: 2579: 2576: 2573: 2569: 2565: 2559: 2556: 2549: 2542: 2539: 2534: 2531: 2526: 2522: 2515: 2513: 2504: 2497: 2493: 2489: 2486: 2483: 2477: 2474: 2468: 2464: 2460: 2457: 2454: 2448: 2444: 2437: 2434: 2429: 2426: 2421: 2417: 2410: 2408: 2400: 2394: 2383: 2382: 2381: 2367: 2357: 2338: 2330: 2326: 2322: 2306: 2301: 2293: 2289: 2285: 2279: 2276: 2273: 2270: 2262: 2254: 2250: 2246: 2230: 2227: 2223: 2214: 2209: 2201: 2193: 2189: 2185: 2179: 2176: 2172: 2163: 2158: 2146: 2129: 2125: 2121: 2118: 2115: 2109: 2106: 2100: 2096: 2092: 2089: 2086: 2080: 2072: 2071:Taylor series 2056: 2053: 2050: 2022: 2016: 2012: 2008: 2005: 1995: 1987: 1983: 1979: 1976: 1973: 1969: 1965: 1959: 1956: 1950: 1945: 1941: 1937: 1934: 1924: 1916: 1912: 1908: 1905: 1902: 1898: 1894: 1888: 1885: 1878: 1871: 1868: 1863: 1860: 1855: 1851: 1844: 1842: 1833: 1826: 1822: 1818: 1815: 1812: 1806: 1803: 1797: 1793: 1789: 1786: 1783: 1777: 1773: 1766: 1763: 1758: 1755: 1750: 1746: 1739: 1737: 1729: 1723: 1712: 1711: 1710: 1696: 1688: 1672: 1668: 1664: 1661: 1658: 1655: 1645: 1632: 1624: 1616: 1612: 1608: 1592: 1587: 1579: 1575: 1571: 1563: 1560: 1555: 1552: 1549: 1543: 1537: 1528: 1526: 1525:Taylor series 1507: 1503: 1499: 1496: 1483: 1475: 1471: 1467: 1461: 1458: 1452: 1446: 1440: 1420: 1417: 1414: 1391: 1385: 1382: 1377: 1374: 1369: 1365: 1355: 1349: 1346: 1340: 1332: 1328: 1320: 1319: 1318: 1316: 1312: 1308: 1304: 1300: 1296: 1292: 1269: 1265: 1261: 1258: 1248: 1240: 1236: 1232: 1226: 1223: 1217: 1211: 1205: 1198: 1182: 1175: 1159: 1152: 1149: 1132: 1125: 1124: 1109: 1101: 1091: 1088: 1084: 1080: 1077: 1074: 1066: 1056: 1053: 1049: 1045: 1042: 1039: 1031: 1012: 1008: 1000: 999: 998: 981: 975: 972: 967: 962: 958: 948: 942: 939: 931: 927: 923: 913: 909: 905: 900: 896: 889: 882: 878: 874: 869: 865: 858: 852: 844: 840: 832: 831: 830: 828: 820: 818: 797: 787: 784: 780: 776: 773: 770: 761: 743: 739: 715: 710: 706: 703: 698: 694: 685: 681: 677: 671: 666: 663: 658: 652: 649: 642: 641: 640: 638: 634: 630: 625: 611: 607: 603: 600: 597: 594: 574: 570: 566: 544: 540: 517: 513: 504: 488: 485: 482: 462: 454: 453:Taylor series 450: 439: 432: 425: 418: 411: 404: 397: 390: 383: 378: 371: 366: 358: 351: 349: 347: 342: 338: 322: 318: 310: 306: 301: 276: 254: 250: 242: 238: 233: 208: 205: 200: 196: 188: 184: 179: 154: 151: 148: 139: 137: 121: 101: 89: 83: 79: 77: 73: 69: 64: 61: 57: 53: 49: 40: 32: 19: 4178: 4144: 4099:cite journal 4091:the original 4080: 4066: 4055:. Retrieved 4051: 4042: 4031:. Retrieved 4027: 4000: 3981: 3970:. Retrieved 3966:the original 3956: 3938: 3919: 3913: 3864:Maxwell coil 3810: 3807:Maxwell coil 3798: 3569: 3554: 3545: 3534: 3525: 3517: 3513: 3501: 3495: 3351: 3340: 3317: 3294: 3175: 3169: 3166: 3074: 3065: 2815: 2713: 2359: 2148: 2042: 1647: 1530: 1406: 1317:-turn coil: 1314: 1310: 1306: 1302: 1298: 1294: 1290: 1288: 996: 824: 730: 636: 632: 628: 626: 446: 437: 430: 429:, 1.05  423: 422:, 1.01  416: 415:, 0.99  409: 408:, 0.95  402: 395: 388: 381: 369: 343: 339: 140: 93: 67: 65: 47: 45: 4166:derivatives 401:, 0.9  394:, 0.8  352:Mathematics 90:Description 4218:Categories 4164:and their 4057:2016-02-25 4033:2016-01-27 4022:Yang, KC. 3972:2007-11-20 3906:References 2380:would be: 2069:, and the 1709:would be: 821:Derivation 3892:cusp trap 3716:π 3631:π 3381:ω 3273:⋅ 3260:− 3252:× 3238:⋅ 3225:− 3217:× 3214:π 3185:μ 3137:μ 2978:− 2955:≈ 2864:− 2777:ξ 2774:− 2757:− 2748:ξ 2725:≪ 2677:− 2622:− 2606:− 2577:− 2523:μ 2478:ξ 2475:− 2458:− 2449:ξ 2418:μ 2277:− 2271:≈ 2180:− 2110:ξ 2090:− 2081:ξ 2054:≪ 2006:− 1935:− 1906:− 1852:μ 1807:ξ 1787:− 1778:ξ 1747:μ 1685:, so the 1662:± 1556:− 1538:ξ 1497:− 1441:ξ 1418:≪ 1366:μ 1350:ξ 1259:− 1206:ξ 1102:⋅ 1089:− 1081:× 1067:⋅ 1054:− 1046:× 1043:π 1009:μ 959:μ 943:ξ 866:μ 798:⋅ 785:− 777:× 774:π 740:μ 695:μ 601:± 315:∂ 298:∂ 247:∂ 230:∂ 193:∂ 176:∂ 4200:Archived 4187:archived 3990:Archived 3946:Archived 3876:Solenoid 3870:See also 141:Setting 72:gradient 4170:PBworks 4160:, uses 3799:(hoops) 3269: T 3234: T 1687:B-field 1301:in the 1148:amperes 1098: T 1063: T 794: T 758:is the 3926:  3496:where 3176:where 1028:= the 731:where 501:is an 4190:(PDF) 4183:(PDF) 3249:1.257 1078:1.257 997:Here 4119:link 4112:help 3924:ISBN 3552:and 3532:and 2981:1.83 2958:1.72 2280:1.65 2274:1.43 2228:3125 2210:2304 1407:For 1309:for 4028:EDN 3835:to 3516:= 2 3277:m/A 3242:m/A 2912:625 2894:512 2861:125 2812:is: 2145:is: 2073:of 1527:as: 1106:m/A 1071:m/A 802:m/A 4220:: 4103:: 4101:}} 4097:{{ 4050:. 4026:. 4014:^ 3885:A 3866:. 3518:πf 3256:10 3221:10 3173:. 2843:96 2177:25 2159:16 1307:nI 1085:10 1050:10 1032:= 829:: 817:. 781:10 624:. 337:. 46:A 4172:. 4153:. 4121:) 4114:) 4110:( 4074:. 4060:. 4036:. 4008:. 3975:. 3932:. 3850:R 3845:3 3823:R 3769:) 3763:2 3759:L 3755:+ 3750:1 3746:L 3741:( 3735:2 3730:) 3724:0 3720:f 3713:2 3709:( 3703:1 3698:= 3695:C 3669:C 3665:) 3659:2 3655:L 3651:+ 3646:1 3642:L 3637:( 3628:2 3624:1 3619:= 3614:0 3610:f 3584:0 3580:f 3558:2 3555:R 3549:1 3546:R 3538:2 3535:L 3529:1 3526:L 3521:, 3514:ω 3509:ω 3502:I 3477:2 3471:) 3463:2 3459:R 3455:+ 3450:1 3446:R 3440:( 3435:+ 3430:2 3424:] 3416:) 3409:2 3405:L 3401:+ 3396:1 3392:L 3386:( 3376:[ 3369:I 3366:= 3363:V 3325:R 3302:I 3281:, 3263:6 3246:= 3228:7 3211:4 3189:0 3170:B 3152:) 3146:n 3141:0 3131:R 3128:B 3122:( 3116:2 3112:/ 3108:3 3103:) 3098:4 3095:5 3090:( 3085:= 3082:I 3057:. 3045:) 3040:5 3036:) 3032:R 3028:/ 3024:x 3021:( 3018:( 3013:O 3008:+ 3003:3 2999:) 2995:R 2991:/ 2987:x 2984:( 2975:) 2972:R 2968:/ 2964:x 2961:( 2952:) 2947:5 2943:) 2939:R 2935:/ 2931:x 2928:( 2925:( 2920:O 2915:+ 2908:/ 2904:) 2899:5 2891:( 2886:3 2882:) 2878:R 2874:/ 2870:x 2867:( 2857:/ 2853:) 2848:5 2840:( 2837:) 2834:R 2830:/ 2826:x 2823:( 2800:) 2797:2 2793:/ 2789:R 2786:+ 2783:x 2780:( 2771:) 2768:2 2764:/ 2760:R 2754:x 2751:( 2728:R 2722:x 2694:) 2688:2 2684:/ 2680:3 2673:] 2667:2 2663:) 2659:2 2655:/ 2651:1 2648:+ 2645:R 2641:/ 2637:x 2634:( 2631:+ 2628:1 2625:[ 2617:2 2613:/ 2609:3 2602:] 2596:2 2592:) 2588:2 2584:/ 2580:1 2574:R 2570:/ 2566:x 2563:( 2560:+ 2557:1 2554:[ 2550:( 2543:R 2540:2 2535:I 2532:n 2527:0 2516:= 2505:] 2501:) 2498:2 2494:/ 2490:R 2487:+ 2484:x 2481:( 2472:) 2469:2 2465:/ 2461:R 2455:x 2452:( 2445:[ 2438:R 2435:2 2430:I 2427:n 2422:0 2411:= 2404:) 2401:x 2398:( 2395:B 2368:x 2356:. 2344:) 2339:6 2335:) 2331:R 2327:/ 2323:x 2320:( 2317:( 2312:O 2307:+ 2302:4 2298:) 2294:R 2290:/ 2286:x 2283:( 2268:) 2263:6 2259:) 2255:R 2251:/ 2247:x 2244:( 2241:( 2236:O 2231:+ 2224:/ 2220:) 2215:5 2207:( 2202:4 2198:) 2194:R 2190:/ 2186:x 2183:( 2173:/ 2169:) 2164:5 2156:( 2133:) 2130:2 2126:/ 2122:R 2119:+ 2116:x 2113:( 2107:+ 2104:) 2101:2 2097:/ 2093:R 2087:x 2084:( 2057:R 2051:x 2023:) 2017:2 2013:/ 2009:3 2002:] 1996:2 1992:) 1988:2 1984:/ 1980:1 1977:+ 1974:R 1970:/ 1966:x 1963:( 1960:+ 1957:1 1954:[ 1951:+ 1946:2 1942:/ 1938:3 1931:] 1925:2 1921:) 1917:2 1913:/ 1909:1 1903:R 1899:/ 1895:x 1892:( 1889:+ 1886:1 1883:[ 1879:( 1872:R 1869:2 1864:I 1861:n 1856:0 1845:= 1834:] 1830:) 1827:2 1823:/ 1819:R 1816:+ 1813:x 1810:( 1804:+ 1801:) 1798:2 1794:/ 1790:R 1784:x 1781:( 1774:[ 1767:R 1764:2 1759:I 1756:n 1751:0 1740:= 1733:) 1730:x 1727:( 1724:B 1697:x 1673:2 1669:/ 1665:R 1659:= 1656:x 1633:. 1630:) 1625:4 1621:) 1617:R 1613:/ 1609:x 1606:( 1603:( 1598:O 1593:+ 1588:2 1584:) 1580:R 1576:/ 1572:x 1569:( 1564:2 1561:3 1553:1 1550:= 1547:) 1544:x 1541:( 1508:2 1504:/ 1500:3 1493:] 1489:) 1484:2 1480:) 1476:R 1472:/ 1468:x 1465:( 1462:+ 1459:1 1456:[ 1453:= 1450:) 1447:x 1444:( 1421:R 1415:x 1392:. 1386:R 1383:2 1378:I 1375:n 1370:0 1359:) 1356:x 1353:( 1347:= 1344:) 1341:x 1338:( 1333:1 1329:B 1315:n 1311:I 1303:n 1299:I 1295:n 1291:n 1270:2 1266:/ 1262:3 1255:] 1249:2 1245:) 1241:R 1237:/ 1233:x 1230:( 1227:+ 1224:1 1221:[ 1218:= 1215:) 1212:x 1209:( 1183:x 1160:R 1150:, 1133:I 1110:, 1092:6 1075:= 1057:7 1040:4 1013:0 982:. 976:R 973:2 968:I 963:0 952:) 949:x 946:( 940:= 932:2 928:/ 924:3 920:) 914:2 910:x 906:+ 901:2 897:R 893:( 890:2 883:2 879:R 875:I 870:0 859:= 856:) 853:x 850:( 845:1 841:B 815:) 788:7 771:4 763:( 744:0 716:, 711:R 707:I 704:n 699:0 686:2 682:/ 678:3 672:) 667:5 664:4 659:( 653:= 650:B 637:I 633:n 629:R 612:2 608:/ 604:R 598:= 595:x 575:2 571:/ 567:R 545:4 541:x 518:2 514:x 489:0 486:= 483:x 463:x 443:. 441:0 438:B 434:0 431:B 427:0 424:B 420:0 417:B 413:0 410:B 406:0 403:B 399:0 396:B 392:0 389:B 385:0 382:B 370:z 323:2 319:x 311:/ 307:B 302:2 277:h 255:4 251:x 243:/ 239:B 234:4 209:0 206:= 201:2 197:x 189:/ 185:B 180:2 155:R 152:= 149:h 122:R 102:h 20:)

Index

Quadrupole magnetic field


magnetic field
Hermann von Helmholtz
electromagnets
gradient
magnetic traps

electric current
Earth's magnetic field



Bessel functions
Taylor series
inflection point
permeability of free space
Biot–Savart law
permeability constant
amperes
Taylor series
B-field
Taylor series


Maxwell coil
James Clerk Maxwell
Maxwell coil
Solenoid

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