From 0ed7c6167e225d1a026272276b6a1db6b2f3a417 Mon Sep 17 00:00:00 2001
From: Gamelin Alexis <alexis.gamelin@synchrotron-soleil.fr>
Date: Thu, 29 Jun 2023 19:14:20 +0200
Subject: [PATCH] Add loss_factor computation for WakeFunction
Change the default binning for WakePotential to 80 (better value for most cases).
---
mbtrack2/impedance/wakefield.py | 30 ++++++++++++++++++++++++++++++
mbtrack2/tracking/wakepotential.py | 2 +-
2 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/mbtrack2/impedance/wakefield.py b/mbtrack2/impedance/wakefield.py
index 5de4a8f..3171251 100644
--- a/mbtrack2/impedance/wakefield.py
+++ b/mbtrack2/impedance/wakefield.py
@@ -277,6 +277,8 @@ class WakeFunction(ComplexData):
Compute a wake function from wake potential data.
plot()
Plot the wake function data.
+ loss_factor(sigma)
+ Compute the loss factor or the kick factor for a Gaussian bunch.
"""
def __init__(self,
@@ -454,6 +456,34 @@ class WakeFunction(ComplexData):
label = r"$W_{" + self.component_type + r"}$" + unit
ax.set_ylabel(label)
return ax
+
+ def loss_factor(self, sigma):
+ """
+ Compute the loss factor or the kick factor for a Gaussian bunch.
+ Formulas from Eq. (5.6), Eq. (5.12) and Eq. (5.17) of [1].
+
+ Parameters
+ ----------
+ sigma : float
+ RMS bunch length in [s]
+
+ Returns
+ -------
+ kloss: float
+ Loss factor in [V/C] or kick factor in [V/C/m] depanding on the
+ impedance type.
+
+ References
+ ----------
+ [1] : Zotter, Bruno W., and Semyon A. Kheifets. Impedances and wakes
+ in high-energy particle accelerators. World Scientific, 1998.
+
+ """
+ time = self.data.index
+ S = 1/(2*np.sqrt(np.pi)*sigma)*np.exp(-1*time**2/(4*sigma**2))
+ kloss = trapz(x = time, y = self.data["real"]*S)
+
+ return kloss
class Impedance(ComplexData):
"""
diff --git a/mbtrack2/tracking/wakepotential.py b/mbtrack2/tracking/wakepotential.py
index 14ac151..43a1692 100644
--- a/mbtrack2/tracking/wakepotential.py
+++ b/mbtrack2/tracking/wakepotential.py
@@ -70,7 +70,7 @@ class WakePotential(Element):
"""
- def __init__(self, ring, wakefield, n_bin=65):
+ def __init__(self, ring, wakefield, n_bin=80):
self.wakefield = wakefield
self.types = self.wakefield.wake_components
self.n_types = len(self.wakefield.wake_components)
--
GitLab