Summary
We describe an approximation we have used to compute gain, saturation and electron statistics at high power in the Stanford free-electron laser.
Riassunto
Si descrive un'approssimazione usata per calcolare il guadagno, la saturazione e la statistica degli elettroni ad alta potenza nel laser a elettroni liberi di Stanford.
Резюме
Мы описываем приближенный метод, который исполязуется для вычисления усиления, насыщения и статистики электронов при больших мощностях в свободном электронном лазере с Стенфорде.
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Abbreviations
- e :
-
electron charge (4.8·10−10 statcoulomb)
- m :
-
electron mass (9.11·10−28 g)
- c :
-
speed of light (3·1010 cm s−1)
- ℏ:
-
Planck's constant (1.05·10−27 erg s)
- K :
-
Boltzmann's constant (1.38·10−16 erg K−1)
- r :
-
exact electron position
- r a :
-
approximate electron position calculated by using the approximation described in the text for the analysis of the electron motion in the presence of the optical field
- δr=r−r a :
-
position error
- \(\delta r_1 = (\delta r \cdot \hat z)\hat z\) :
-
longitudinal position error
- δr ⊥=δr−δr ⊥ :
-
transverse position error
- \(\beta= \dot r/c\) :
-
exact normalized electron velocity
- β0 :
-
normalized electron velocity when the optical field is absent
- \(\hat \beta _0 = \beta _0 /|\beta _0 |\) :
-
unit vector for normalized velocity when the optical field is absent
- βa :
-
approximate normalized velocity, calculated by using the approximation described in the text to analyze the electron motion in the presence of the optical field
- \(\beta _\parallel = (\beta _a \cdot \hat z)\hat z\) :
-
normalized approximate longitudinal velocity
- β⊥=βa−β∥ :
-
normalized approximate transverse velocity
- δβ=β−βa :
-
normalized velocity error
- \(\delta \beta _\parallel = (\delta \beta \cdot \hat z)\hat z\) :
-
normalized longitudinal-velocity error
- δβ⊥=δβ−δβ‖ :
-
normalized transverse-velocity error
- P :
-
exact electron momentum (g cm s−1)
- P 0 :
-
electron momentum when the optical field is absent
- P a :
-
approximate electron momentum calculated by using the approximation described in the text for the analysis of the electron motion in the presence of the optical field
- δp=p−p a :
-
momentum error
- \(\delta p_\parallel = (\delta p \cdot \hat z)\hat z\) :
-
longitudinal-momentum error
- δp ⊥=δp−δp‖:
-
transverse-momentum error
- \(\gamma = \sqrt {p^2 + m^2 c^2 } /mc\) :
-
exact normalized electron mass-energy
- γa :
-
approximate electron mass-energy, calculated by using the approximation described in the text for the analysis of the electron motion in the presence of the optical field
- δγ = γ-γa :
-
error in normalized energy.
- ω:
-
optical frequency (s−1)
- k :
-
optical wave vector (cm−1)
- \(\hat k = k/\left| k \right|\) :
-
unit wave vector
- E :
-
optical electric field (statvolt cm−1)
- B :
-
optical magnetic field (G)
- E 0 :
-
polarization vector for optical electric field
- S lab :
-
optical power density (erg cm−2 s−1)
- λq :
-
magnet period (cm)
- L :
-
length (cm)
- B 0 :
-
static magnetic field (G)
- B 0 :
-
polarization vector for the static magnetic field
- A :
-
vector potential for the static magnetic field
- \(A_ \bot = A - (A \cdot \hat z)\hat z\) :
-
transverse component of vector potential.
- t :
-
dummy variable for time
- T :
-
total interaction time (s)
- K D :
-
Debye wave number
- n 0 :
-
electron density (cm−3)
- τ:
-
temperature (K).
References
J. M. J. Madey andD. A. G. Deacon: inCo-Operative Effects in Matter and Radiation, edited byC. M. Bowden, D. W. Howgate andH. H. Robl (New York, N. Y., 1977), p. 313.
R. M. Phillips:IRE Trans. Elect. Dev.,1, 231 (1960).
F. A. Hopf, P. Meystre, M. O. Scully andW. H. Louisell:Opt. Comm.,18, 413 (1976);F. A. Hopf, P. Meystre, M. O. Scully andW. H. Louisell:Phys. Rev. Lett.,37, 1342 (1976);H. Al-Abawi, F. A. Hopf andP. Meystre:Phys. Rev. A,16, 666 (1977).
W. B. Colson:Phys. Lett.,64 A, 190 (1977).
A. Bambini andA. Renieri:Nuovo Cimento,21 B, 399 (1978).
V. N. Baier andA. I. Milstein:Phys. Lett.,65 A, 319 (1978).
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Madey, J.M.J., Deacon, D.A.G., Elias, L.R. et al. An approximate technique for the integration on the equations of motion in a free-electron laser. Nuov Cim B 51, 53–69 (1979). https://doi.org/10.1007/BF02743696
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DOI: https://doi.org/10.1007/BF02743696