From 628a21fb3bbea61bb1223657a2a9cd0cf1841bc5 Mon Sep 17 00:00:00 2001
From: Watanyu Foosang <watanyu.f@gmail.com>
Date: Wed, 16 Mar 2022 17:48:01 +0100
Subject: [PATCH] Add RWMBI growth rate and threshold calculation + correct
typos
---
collective_effects/__init__.py | 1 +
collective_effects/impedance_model.py | 24 +++----
collective_effects/instabilities.py | 100 ++++++++++++++++++++++++++
tracking/wakepotential.py | 2 +-
4 files changed, 114 insertions(+), 13 deletions(-)
diff --git a/collective_effects/__init__.py b/collective_effects/__init__.py
index 2740b8b..a23651b 100644
--- a/collective_effects/__init__.py
+++ b/collective_effects/__init__.py
@@ -6,6 +6,7 @@ Created on Tue Jan 14 12:25:30 2020
"""
from mbtrack2.collective_effects.instabilities import mbi_threshold, cbi_threshold, lcbi_growth_rate_mode, lcbi_growth_rate
+from mbtrack2.collective_effects.instabilities import rwmbi_growth_rate, rwmbi_threshold
from mbtrack2.collective_effects.resistive_wall import (skin_depth, CircularResistiveWall, Coating)
from mbtrack2.collective_effects.resonator import Resonator, PureInductive, PureResistive
from mbtrack2.collective_effects.tapers import StupakovRectangularTaper, StupakovCircularTaper
diff --git a/collective_effects/impedance_model.py b/collective_effects/impedance_model.py
index 8c86251..e2b1ef2 100644
--- a/collective_effects/impedance_model.py
+++ b/collective_effects/impedance_model.py
@@ -25,7 +25,7 @@ class ImpedanceModel(Element):
ring : Synchrotron object
wakefield_list : list of WakeField objects
WakeFields to add to the model.
- wakefiled_postions : list
+ wakefiled_positions : list
Longitudinal positions corresponding to the added Wakfields.
Attributes
@@ -45,9 +45,9 @@ class ImpedanceModel(Element):
Methods
-------
- add(wakefield_list, wakefiled_postions)
+ add(wakefield_list, wakefiled_positions)
Add elements to the model.
- add_multiple_elements(wakefield, wakefiled_postions)
+ add_multiple_elements(wakefield, wakefiled_positions)
Add the same element at different locations to the model.
sum_elements()
Sum all WakeFields into self.sum.
@@ -63,14 +63,14 @@ class ImpedanceModel(Element):
Plot the contributions of different kind of WakeFields.
"""
- def __init__(self, ring, wakefield_list=None, wakefiled_postions=None):
+ def __init__(self, ring, wakefield_list=None, wakefiled_positions=None):
self.ring = ring
self.optics = self.ring.optics
self.wakefields = []
self.positions = np.array([])
self.names = np.array([])
self.sum_names = np.array([])
- self.add(wakefield_list, wakefiled_postions)
+ self.add(wakefield_list, wakefiled_positions)
def track(self, beam):
"""
@@ -152,7 +152,7 @@ class ImpedanceModel(Element):
for name in self.names:
self.sum_by_name(name)
- def add(self, wakefield_list, wakefiled_postions):
+ def add(self, wakefield_list, wakefiled_positions):
"""
Add elements to the model.
@@ -160,19 +160,19 @@ class ImpedanceModel(Element):
----------
wakefield_list : list of WakeField objects
WakeFields to add to the model.
- wakefiled_postions : list
+ wakefiled_positions : list
Longitudinal positions corresponding to the added Wakfields.
"""
- if (wakefield_list is not None) and (wakefiled_postions is not None):
+ if (wakefield_list is not None) and (wakefiled_positions is not None):
for wakefield in wakefield_list:
self.wakefields.append(wakefield)
- for position in wakefiled_postions:
+ for position in wakefiled_positions:
self.positions = np.append(self.positions, position)
self.update_name_list()
- def add_multiple_elements(self, wakefield, wakefiled_postions):
+ def add_multiple_elements(self, wakefield, wakefiled_positions):
"""
Add the same element at different locations to the model.
@@ -180,10 +180,10 @@ class ImpedanceModel(Element):
----------
WakeField : WakeField object
WakeField to add to the model.
- wakefiled_postions : list
+ wakefiled_positions : list
Longitudinal positions corresponding to the added Wakfield.
"""
- for position in wakefiled_postions:
+ for position in wakefiled_positions:
self.positions = np.append(self.positions, position)
self.wakefields.append(wakefield)
diff --git a/collective_effects/instabilities.py b/collective_effects/instabilities.py
index 1fe58ec..99842e9 100644
--- a/collective_effects/instabilities.py
+++ b/collective_effects/instabilities.py
@@ -8,6 +8,7 @@ General calculations about instabilities
import numpy as np
import matplotlib.pyplot as plt
from scipy.constants import c, m_e, e, pi, epsilon_0
+import math
def mbi_threshold(ring, sigma, R, b):
"""
@@ -251,6 +252,105 @@ def plot_critical_mass(ring, bunch_charge, bunch_spacing, n_points=1e4):
ax.set_xlabel("Longitudinal position [m]")
return fig
+
+def rwmbi_growth_rate(ring, current, beff, rho_material, plane='x'):
+ """
+ Compute the growth rate of the transverse coupled-bunch instability induced
+ by resistive wall impedance [1].
+
+ Parameters
+ ----------
+ ring : Synchrotron object
+ current : float
+ Total beam current in [A].
+ beff : float
+ Effective radius of the vacuum chamber in [m].
+ rho_material : float
+ Resistivity of the chamber's wall material in [Ohm.m].
+ plane : str, optional
+ The plane in which the instability will be computed. Use 'x' for the
+ horizontal plane, and 'y' for the vertical.
+
+ Reference
+ ---------
+ [1] Eq. (31) in R. Nagaoka and K. L. F. Bane, "Collective effects in a
+ diffraction-limited storage ring", J. Synchrotron Rad. Vol 21, 2014. pp.937-960
+
+ """
+ plane_dict = {'x':0, 'y':1}
+ index = plane_dict[plane]
+ beta0 = ring.optics.local_beta[index]
+ omega0 = ring.omega0
+ E0 = ring.E0
+ R = ring.L/(2*np.pi)
+ frac_tune, int_tune = math.modf(ring.tune[index])
+ Z0 = 377.7 # Vacuum impedance [Ohm]
+
+ gr = (beta0*omega0*current*R) /(4*np.pi*E0*beff**3) * ((2*c*Z0*rho_material) / ((1-frac_tune)*omega0))**0.5
+
+ return gr
+
+def rwmbi_threshold(ring, beff, rho_material, plane='x'):
+ """
+ Compute the threshold current of the transverse coupled-bunch instability
+ induced by resistive wall impedance [1].
+
+ Parameters
+ ----------
+ ring : Synchrotron object
+ beff : float
+ Effective radius of the vacuum chamber in [m].
+ rho_material : float
+ Resistivity of the chamber's wall material in [Ohm.m].
+ plane : str, optional
+ The plane in which the instability will be computed. Use 'x' for the
+ horizontal plane, and 'y' for the vertical.
+
+ Reference
+ ---------
+ [1] Eq. (32) in R. Nagaoka and K. L. F. Bane, "Collective effects in a
+ diffraction-limited storage ring", J. Synchrotron Rad. Vol 21, 2014. pp.937-960
+
+ """
+ plane_dict = {'x':0, 'y':1}
+ index = plane_dict[plane]
+ beta0 = ring.optics.local_beta[index]
+ omega0 = ring.omega0
+ E0 = ring.E0
+ tau_rad = ring.tau[index]
+ frac_tune, int_tune = math.modf(ring.tune[index])
+ Z0 = 377.7 # Vacuum impedance [Ohm]
+
+ Ith = (4*np.pi*E0*beff**3) / (c*beta0*tau_rad) * (((1-frac_tune)*omega0) / (2*c*Z0*rho_material))**0.5
+
+ return Ith
+
+
+
+
+
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+
+
+
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+
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+
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+
\ No newline at end of file
diff --git a/tracking/wakepotential.py b/tracking/wakepotential.py
index 9910c6d..223dd43 100644
--- a/tracking/wakepotential.py
+++ b/tracking/wakepotential.py
@@ -703,7 +703,7 @@ class LongRangeResistiveWall(Element):
of mass with respect to center of the RF bucket number 0 at turn j.
Turn 0 corresponds to the tracked turn.
- Postive time corresponds to past events and negative time to future
+ Positive time corresponds to past events and negative time to future
events.
Parameters
--
GitLab