From 2b93c2d90fb152c6a87720db39c608225fc31ea5 Mon Sep 17 00:00:00 2001
From: Gamelin Alexis <alexis.gamelin@synchrotron-soleil.fr>
Date: Fri, 19 Nov 2021 11:29:51 +0100
Subject: [PATCH] [Fix] CircularResistiveWall
Correct scale for the exact TransverseWakeFunction in CircularResistiveWall.
Thanks to Keon Hee Kim for providing the correction factor.
---
collective_effects/resistive_wall.py | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/collective_effects/resistive_wall.py b/collective_effects/resistive_wall.py
index 08500d4..dc4c4ba 100644
--- a/collective_effects/resistive_wall.py
+++ b/collective_effects/resistive_wall.py
@@ -46,9 +46,7 @@ class CircularResistiveWall(WakeField):
Impedance from approximated formulas from Eq. (2.77) of Chao book [1].
Wake function formulas from [2].
-
- !!! The exact formula for the transverse wake function is wrong !!!
-
+
Parameters
----------
time : array of float
@@ -163,6 +161,8 @@ class CircularResistiveWall(WakeField):
using Eq. (25), or approxmiated expression Eq. (26), of [1]. The
approxmiated expression is valid if the time is large compared to the
characteristic time t0.
+
+ Exact expression (Eq. (25) from [1]) is corrected by factor (c * t0).
Parameters
----------
@@ -188,7 +188,7 @@ class CircularResistiveWall(WakeField):
if exact==True:
self.t0 = (2*self.rho*self.radius**2 / Z0)**(1/3) / c
- factor = 8*Z0*c/(np.pi * self.radius**4) * self.length * -1
+ factor = -1 * (8 * Z0 * c**2 * self.t0) / (np.pi * self.radius**4) * self.length
wt = np.zeros_like(time)
for i, t in enumerate(time):
--
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