Apochromatic focusing example #487
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- Modified the initial beam size in the IOTA lens benchmark example. - Added 2 benchmarks of 3D space charge for initial testing. - Add documentation for 2 benchmarks with space charge. - Add a benchmark example with space charge and periodic s-dependent focusing. - Added an s-dependent example using a Kurth beam without space charge. - Modified tolerance for IOTA lens benchmark example. Reduced tolerance to account for smaller initial beam size and improved preservation of invariants of motion. - Modified tolerances of space charge examples to allow CI tests to pass when space charge is not active. - Modified tolerance for space charge examples. These should fail unless space charge is turned on.
Selected numerical values for amr.n_cell, lattice.nslice, and geometry.prob_relative.
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Not part of this PR.
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Emittance growth observed in ImpactX: 0.5% Note that Lindstrom (and ELEGANT) both use the non-canonical variables (x',y') while ImpactX always uses the canonical variables (px/p0,py/p0). For small relative energy spread, these are essentially equivalent. When energy spread becomes large, this difference becomes important. This may be the source of the difference: investigating this now. I modified the analysis script to use (x',y') as momentum variables for computing the emittance, and this effect is far too small to account for this difference (~0.02%). Solution: The original ImpactX input used a 6D waterbag distribution, while Lindstrom et al assumes a Gaussian distribution in energy. Changing to a 6D gaussian distribution and using the (x',y') variables above yields an emittance growth of 0.94%. |
Change to a Gaussian distribution.
Change to a gaussian distribution.
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Nice! Great reconstruction of events 🕵️ 😄 |
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Correct CMakeLists specification.
Correct misspelling.
Update Python to 10^5 particles
Python distribution type should be Gaussian.
Added example input files for the drift-quad apochromatic focusing lattice shown in Fig. 4a of:
C. A. Lindstrom and E. Adli, Phys. Rev. Accel. Beams 19, 071002 (2016),
https://doi.org/10.1103/PhysRevAccelBeams.19.071002