13.4 Highlights of What’s New in Version 2023.1

Here is a summary of what’s changed since release 2022.2.

13.4.1 Bug Fixes for Elements

• The CCBEND element had a bug in the path-length correction feature that affected runs in which the optimization of fractional strength error or transverse offset was repeated. This could result in a mismatch between the rf frequency and path-length, for example. M. Venturini (LBNL) reported the issue.
• Z. Duan (IHEP) reported an issue with misalignment methods 1 and 2 for CSBEND elements when when TILT was nonzero, which he identified as an error in the code that incorrectly used TILT and ETILT in combination. This was fixed, but in the process it proved advisable to change the order of operations to conform to the original one in elegant; in particular, mislignments now occur in the untilted frame in all cases except CCBEND elements. In addition, we added the ability to select either the linearized or exact Venturini algorithm by adding two new modes. In particular,
  • Method 0 — This selects the original method, which was the only one available before version 2021.1. The misalignment is referenced to the entrance face. Yaw and pitch errors are not supported.
  • Method 1 — This selects a linearized method based on M. Venturini’s work [58], with misalignment referenced to the entrance face. Yaw and pitch errors are supported.
  • Method 2 — This selects a linearized method based on M. Venturini’s work [58], with misalignment referenced to the magnet center. Yaw and pitch errors are supported.
  • Method 3 — This selects an exact method based on M. Venturini’s work [58], with misalignment referenced to the entrance face. Yaw and pitch errors are supported.
  • Method 4 — This selects an exact method based on M. Venturini’s work [58], with misalignment referenced to the magnet center. Yaw and pitch errors are supported.
• The C matrix component for MATR elements was ignored, with the exception of the C[4] (path-length) component.

13.4.2 New and Modified Elements

• CCBEND now has a parameter, REFERENCE_CORRECTION that permits turning on correction of residual trajectory errors due to limited accuracy in optimization of the reference trajectory.
• RFCA and RFCW now optionally include body focusing terms for a pure sinusoidal traveling wave. This deficiency was pointed out by B. Simona (PSI).
• The CKICKER element, used as the kicker for simulation of optical stochastic cooling, was improved by the main author, A. J. Dick. Improvements include
  • Corrected the upper bound of integration in XYZ.
  • Corrected bugs in computation of incoherent effects.
  • The envelope function is now applied correctly to both coherent and incoherent kicks.
  • Corrected some mistakes in the documentation.
• The LGBEND element now supports yaw and pitch misalignments.

13.4.3 New and Modified Commands

• The touschek_scatter command was interpreting ignored_portion values less than or equal to 10^-6 as zero, under the assumption that typically ~1 million particles would be used. This cut-over now occurs at 10^-9. Forum user Skamarokha reported this issue.

13.4.4 Changes to Related Programs and Files

The elegant distribution includes many programs and scripts that perform computations with elegant output data, provide interfaces with other programs, or prepare data for use with elegant. These are listed in Section 8.

Changes to these tools in this release include

• The straightDipoleFringeCalc program now allows the user to specify the arc length of the CCBEND element, rather than relying on the internal calculation, which may not be accurate.