From e900994be649cd8cc35bee5a189937648f184d3e Mon Sep 17 00:00:00 2001
From: Gamelin Alexis <gamelin@synchrotron-soleil.fr>
Date: Mon, 8 Jun 2020 17:44:54 +0200
Subject: [PATCH] Impedance : energy_loss method for ImpedanceModel + fix on
beam_loss_factor
ImpedanceModel -> new method to compute beam and bunch energy loss
beam_loss_factor -> drop 0 from data only if it is there, avoid bug if it is not
---
collective_effects/tools.py | 5 ++-
collective_effects/wakefield.py | 63 +++++++++++++++++++++++++++++++++
2 files changed, 67 insertions(+), 1 deletion(-)
diff --git a/collective_effects/tools.py b/collective_effects/tools.py
index 606db8b..44c0efc 100644
--- a/collective_effects/tools.py
+++ b/collective_effects/tools.py
@@ -385,7 +385,10 @@ def beam_loss_factor(impedance, frequency, spectrum, ring):
negative_index = impedance.data.index*-1
negative_data = impedance.data.set_index(negative_index)
negative_data["imag"] = -1*negative_data["imag"]
- negative_data = negative_data.drop(0)
+ try:
+ negative_data = negative_data.drop(0)
+ except KeyError:
+ pass
all_data = impedance.data.append(negative_data)
all_data = all_data.sort_index()
diff --git a/collective_effects/wakefield.py b/collective_effects/wakefield.py
index 015221e..4994c4a 100644
--- a/collective_effects/wakefield.py
+++ b/collective_effects/wakefield.py
@@ -738,4 +738,67 @@ class ImpedanceModel(Element):
summary = pd.DataFrame(loss_array.T, index=attr_list,
columns=list_components)
return summary
+
+ def energy_loss(self, sigma, M, bunch_spacing, I, n_points=10e6):
+ """
+ Compute the beam and bunch loss factor and energy losses for each type
+ of element in the model assuming Gaussian bunches and constant spacing
+ between bunches.
+
+ Parameters
+ ----------
+ sigma : float
+ RMS bunch length in [s].
+ M : int
+ Number of bunches in the beam.
+ bunch_spacing : float
+ Time between two bunches in [s].
+ I : float
+ Total beam current in [A].
+ n_points : float, optional
+ Number of points used in the frequency spectrums.
+
+ Returns
+ -------
+ summary : Dataframe
+ Contains the beam and bunch loss factor and energy loss for the
+ full model and for each type of different component.
+
+ """
+
+ fmax = self.sum.Zlong.data.index.max()
+ fmin = self.sum.Zlong.data.index.min()
+
+ Q = I*self.ring.T0/M
+
+ if fmin >= 0:
+ fmin = -1*fmax
+ f = np.linspace(fmin, fmax, int(n_points))
+
+ beam_spect = tools.beam_spectrum(f, M, bunch_spacing, sigma= sigma)
+
+ bunch_spect = tools.Gaussian_bunch_spectrum(f, sigma)
+
+ attr_list = self.sum_names
+
+ loss_array = np.zeros((len(attr_list),2))
+
+ for i, attr in enumerate(attr_list):
+ try:
+ impedance = getattr(getattr(self, attr), "Zlong")
+ loss_array[i,0] = tools.beam_loss_factor(impedance, f, beam_spect, self.ring)
+ loss_array[i,1] = tools.beam_loss_factor(impedance, f, bunch_spect, self.ring)
+ except AttributeError:
+ pass
+
+ loss_array = loss_array*1e-12
+ summary = pd.DataFrame(loss_array, index=attr_list,
+ columns=["loss factor (beam) [V/pC]", "loss factor (bunch) [V/pC]"])
+
+ summary["P (beam) [W]"] = summary["loss factor (beam) [V/pC]"]*1e12*Q**2/(self.ring.T0)
+ summary["P (bunch) [W]"] = summary["loss factor (bunch) [V/pC]"]*1e12*Q**2/(self.ring.T0)*M
+
+ return summary
+
+
\ No newline at end of file
--
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