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63 | 63 | "\\begin{equation}\n",
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64 | 64 | "\\ddot{x} = \\frac{e}{\\gamma m_e} B_y \\dot{z}, \\qquad \\ddot{z} = -\\frac{e}{\\gamma m_e} B_y \\dot{x}\n",
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65 | 65 | "\\end{equation}\n",
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66 |
| - "\n", |
| 66 | + "$$\\qquad$$\n", |
67 | 67 | "In the first order approximation $v_z = \\dot{z} \\approx v = \\beta c = const$, $v_x << v_z$ and $\\ddot{z} \\approx 0$ and taking into account the undulator magnetic field $B_y = -B_0\\sin(k_y z)$ we get:\n",
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68 | 68 | "\n",
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69 | 69 | "\\begin{equation}\n",
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|
76 | 76 | "x(z) = \\frac {K} {\\beta \\gamma k_u}\\sin(k_u z),\n",
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77 | 77 | "\\end{equation}\n",
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78 | 78 | "\n",
|
79 |
| - "where $K = \\frac{eB_0}{m_e c k_u}$\n", |
80 |
| - "\n", |
81 |
| - "and transverse velocity is \n", |
| 79 | + "where $K = \\frac{eB_0}{m_e c k_u}$ and transverse velocity is \n", |
82 | 80 | "\n",
|
83 | 81 | "\\begin{equation}\n",
|
84 | 82 | "v_x(t) = \\frac {K c}{\\gamma} \\cos(k_u \\beta c t) \\qquad or \\qquad v_x(z) = \\frac {K c}{\\gamma} \\cos(k_u z)\n",
|
|
97 | 95 | "\\begin{equation}\n",
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98 | 96 | "v_z = \\sqrt{v^2 - v_x^2} = \\sqrt{c^2(1 - 1/\\gamma^2) - v_x^2} \\approx c\\left(1 - \\frac{1}{2\\gamma^2} (1 + \\gamma^2 v_x^2 / c^2) \\right)\n",
|
99 | 97 | "\\end{equation}\n",
|
100 |
| - "\n", |
| 98 | + "$$\\quad$$\n", |
101 | 99 | "Inserting for $v_x = \\dot{x}(t)$ and using the trigonometric identity $\\cos^2 \\alpha = (1 + \\cos 2 \\alpha)/2$\n",
|
102 | 100 | "\n",
|
103 | 101 | "\\begin{equation}\n",
|
|
136 | 134 | "E(x, y, z) = E_0 \\frac{ e^{-\\frac{1}{2} \\frac{x^2}{\\sigma_x^2 - j z/k} } } {\\sqrt{1-j z/(k \\sigma_x^2)}}\n",
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137 | 135 | "\\frac{ e^{-\\frac{1}{2} \\frac{y^2}{\\sigma_y^2 - j z/k} } } {\\sqrt{1-j z/(k \\sigma_y^2)}}\n",
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138 | 136 | "\\end{equation}\n",
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139 |
| - "\n", |
| 137 | + "$$\\quad$$\n", |
140 | 138 | "Introducing [Rayleigh length](https://en.wikipedia.org/wiki/Rayleigh_length) for $x$ and $y$ plane:\n",
|
141 | 139 | "\n",
|
142 | 140 | "\\begin{equation}\n",
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|
337 | 335 | "\\end{equation}\n",
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338 | 336 | "\n",
|
339 | 337 | "<p>If we ensure fulfillment of the resonance condition only for the first harmonic as we did in the \"Option 1\" (in that case $n=0$) the only one term of the sum will survive the only one term of the sum will survive. Indeed, for the $n=0$ argument of the exponential will be constant but for other harmonic numbers it will oscillate and give in average 0. So our final expression:</p>\n",
|
| 338 | + "\n", |
340 | 339 | "\\begin{equation}\n",
|
341 | 340 | "\\boxed{\\Big \\langle e^{j((k + k_u)\\overline v_z - \\omega) t} \\frac{e^{-j\\theta} + 1}{2} e^{-j Y \\sin\\theta}\\Big\\rangle = \\frac{J_{0}(Y) - J_1(Y)}{2}}\n",
|
342 | 341 | "\\end{equation}\n",
|
|
352 | 351 | "\\begin{equation}\n",
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353 | 352 | "\\langle E v\\rangle = \\frac {K c}{\\gamma} Re \\left\\{ E(x,y,z)\\right\\}\\frac{J_{0}(Y) - J_{1}(Y)}{2}\n",
|
354 | 353 | "\\end{equation}\n",
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355 |
| - "\n", |
| 354 | + "$$\\quad$$\n", |
356 | 355 | "Finally, remembering derivation of the electric field amplitude $E_0 = \\sqrt{\\frac{4 Z_0 \\overline P(0) }{\\pi w^2}}$, we can write expression for amplitude of energy modulation on axis ($x=y=0$)\n",
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357 | 356 | "\n",
|
358 | 357 | "\\begin{equation}\n",
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|
618 | 617 | },
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619 | 618 | {
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620 | 619 | "cell_type": "code",
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621 |
| - "execution_count": 3, |
| 620 | + "execution_count": 1, |
622 | 621 | "metadata": {},
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623 |
| - "outputs": [], |
| 622 | + "outputs": [ |
| 623 | + { |
| 624 | + "name": "stdout", |
| 625 | + "output_type": "stream", |
| 626 | + "text": [ |
| 627 | + "initializing ocelot...\n" |
| 628 | + ] |
| 629 | + } |
| 630 | + ], |
624 | 631 | "source": [
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625 | 632 | "# the output of plotting commands is displayed inline within frontends, \n",
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626 | 633 | "# directly below the code cell that produced it\n",
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678 | 685 | },
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679 | 686 | {
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680 | 687 | "cell_type": "code",
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681 |
| - "execution_count": 4, |
| 688 | + "execution_count": 2, |
682 | 689 | "metadata": {},
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683 | 690 | "outputs": [
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684 | 691 | {
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722 | 729 | },
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723 | 730 | {
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724 | 731 | "cell_type": "code",
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725 |
| - "execution_count": 5, |
| 732 | + "execution_count": 3, |
726 | 733 | "metadata": {},
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727 | 734 | "outputs": [
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728 | 735 | {
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744 | 751 | },
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745 | 752 | {
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746 | 753 | "cell_type": "code",
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747 |
| - "execution_count": 6, |
| 754 | + "execution_count": 4, |
748 | 755 | "metadata": {},
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749 | 756 | "outputs": [
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750 | 757 | {
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772 | 779 | },
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773 | 780 | {
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774 | 781 | "cell_type": "code",
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775 |
| - "execution_count": 7, |
| 782 | + "execution_count": 5, |
776 | 783 | "metadata": {},
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777 | 784 | "outputs": [
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778 | 785 | {
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