def test_correctImpedanceFuncion4(self):
csr_imped = CoherentSynchrotronRadiation(1, gamma=42, chamber_height=4.2)
self.assertTrue(hasattr(csr_imped, 'f_crit'))
self.assertTrue(hasattr(csr_imped, 'f_cut'))
self.assertEqual(csr_imped.imped_calc.__func__,
CoherentSynchrotronRadiation._pp_spectrum)
def test_energyLoss(self):
# based on Example 22: Coherent Radiation
r_bend, energy = 1.273, 40e6 # bending radius [m], particle energy [eV]
gamma = energy / Electron().mass # Lorentz factor
# frequencies at which to compute impedance (from 1e8 to 1e15 Hz)
frequencies = 10**np.linspace(8, 15, num=200)
Z_fs = CoherentSynchrotronRadiation(r_bend, gamma=gamma)
Z_fs.imped_calc(frequencies, low_frequency_transition=1e-4)
energy_loss = 2 * np.trapz(Z_fs.impedance.real, frequencies) * elCharge # [eV]
energy_loss_textbook = Electron().C_gamma * energy**4 / r_bend # [eV]
self.assertAlmostEqual(energy_loss, energy_loss_textbook, places=3)
def test_lowHighFrequencyTransitionFreeSpace(self):
csr_imped = CoherentSynchrotronRadiation(1, gamma=42)
self.assertRaises(ValueError, csr_imped.imped_calc, np.arange(5),
high_frequency_transition=0.2)
self.assertRaises(ValueError, csr_imped.imped_calc, np.arange(5),
low_frequency_transition=2)
self.assertRaises(ValueError, csr_imped.imped_calc, np.arange(5),
low_frequency_transition=1.1, high_frequency_transition=1)
pass
try:
os.mkdir(this_directory + '../output_files/EX_22_fig')
except FileExistsError:
pass
h, r_bend = 32e-3, 1.273 # chamber height [m], bending radius [m]
gamma = 40e6 / Electron().mass # Lorentz factor
# frequencies at which to compute impedance (from 1e8 to 1e15 Hz)
freqs = 10**np.linspace(8, 15, num=200)
# approximate free-space CSR impedance increases as f^2/3
Z_fs_appr = CoherentSynchrotronRadiation(r_bend)
Z_fs_appr.imped_calc(freqs)
# The exact free-space CSR impedance increases as f^2/3 up to the critical frequency...
# ... and is exponentially suppressed above.
Z_fs = CoherentSynchrotronRadiation(r_bend, gamma=gamma)
Z_fs.imped_calc(freqs, high_frequency_transition=10)
f_crit = Z_fs.f_crit # critical frequency [Hz]
# The approximate parallel-plates impedance is suppressed below the cut-off frequency...
# ... and approaches the approximate free-space CSR impedance for large frequencies.
Z_pp_appr = CoherentSynchrotronRadiation(r_bend, chamber_height=h)
Z_pp_appr.imped_calc(freqs, high_frequency_transition=10)
f_cut = Z_pp_appr.f_cut # cut-off frequency [Hz]
def test_correctImpedanceFuncion3(self):
csr_imped = CoherentSynchrotronRadiation(1, chamber_height=42)
self.assertTrue(hasattr(csr_imped, 'f_cut'))
self.assertEqual(csr_imped.imped_calc.__func__,
CoherentSynchrotronRadiation._pp_low_frequency)
def test_correctImpedanceFuncion2(self):
csr_imped = CoherentSynchrotronRadiation(1, gamma=42)
self.assertTrue(hasattr(csr_imped, 'f_crit'))
self.assertEqual(csr_imped.imped_calc.__func__,
CoherentSynchrotronRadiation._fs_spectrum)
def test_correctImpedanceFuncion1(self):
csr_imped = CoherentSynchrotronRadiation(1)
self.assertEqual(csr_imped.imped_calc.__func__,
CoherentSynchrotronRadiation._fs_low_frequency_wrapper)
def test_wrongGamma(self):
with self.assertRaises(ValueError):
CoherentSynchrotronRadiation(1, gamma=0.1)
def test_wrongChamberHeight(self):
with self.assertRaises(ValueError):
CoherentSynchrotronRadiation(1, chamber_height=0)
with self.assertRaises(ValueError):
CoherentSynchrotronRadiation(1, chamber_height=-1)
def test_wrongBendingRadius(self):
with self.assertRaises(ValueError):
CoherentSynchrotronRadiation(-1)
with self.assertRaises(ValueError):
CoherentSynchrotronRadiation(0)
def test_lowHighFrequencyTransitionApproxPP(self):
csr_imped = CoherentSynchrotronRadiation(1, chamber_height=42)
self.assertRaises(ValueError, csr_imped.imped_calc, np.arange(5),
high_frequency_transition=0.2)