--- tags: diagnostics, langmuir, minutes --- # PlasmaPy Langmuir Meeting | Monday 2020 November 23 at 11:00 PT / 14:00 ET [![hackmd-github-sync-badge](https://hackmd.io/cxrk4rDlQlit4XDEXRMoQA/badge)](https://hackmd.io/cxrk4rDlQlit4XDEXRMoQA) ### Video Conference Information * Instant messaging: [Matrix](https://element.im/app/#/room/#plasmapy:openastronomy.org) and [Gitter](https://gitter.im/PlasmaPy/Lobby) * [GitHub Minutes Repository](https://github.com/PlasmaPy/plasmapy-meeting-notes) * [Langmuir Sub-directory](https://github.com/PlasmaPy/plasmapy-meeting-notes/tree/master/langmuir_2020-present) * [PlasmaPy on GitHub](https://github.com/PlasmaPy/plasmapy) ([pull requests](https://github.com/PlasmaPy/plasmapy/pulls), [issues](https://github.com/PlasmaPy/plasmapy/issues)) * [PlasmaPy Enhancement Proposals on GitHub](https://github.com/PlasmaPy/PlasmaPy-PLEPs) * [PlasmaPy Google Calendar](https://calendar.google.com/calendar?cid=bzVsb3ZkcW0zaWxsam00ZTlrMDd2cmw5bWdAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbQ) * GitHub Project: [Prototype | Analysis, Diagnostic, and the Swept Langmuir](https://github.com/PlasmaPy/PlasmaPy/projects/19) ## Attendees 1. Erik 2. Steve 3. Gurleen ## Action Items ***Erik*** * Open PR to update fit_function Linear.root_solve that handles `m = 0` and `b = 0` cases * Finish writing tests for `find_floating_potential()` * Add to list of functionality the ability to find `Te` from fitting to the left side of the dI/dV peak. ***Gurleen*** * Implement a prominence "uncertainty" for `vp` inf `find_plasma_potential_didv()`. * for "uncertainty" will use FWHM of the peak * also report the prominence of the peak ***Future*** * open an issue to construct a metric that considers the signal noise when reporting the peaks "prominence" (`find_plasma_potential_didv()`) ## Agenda (please feel free to edit or add items) 1. Introductions 2. GitHub Project: [Prototype | Analysis, Diagnostic, and the Swept Langmuir](https://github.com/PlasmaPy/PlasmaPy/projects/19) 3. ... 4. ... 5. Issues 1. ... 2. ... 6. Pull requests in progress 1. [PR #889](https://github.com/PlasmaPy/PlasmaPy/pull/889): calculating floating potential 2. [PR #897](https://github.com/PlasmaPy/PlasmaPy/pull/897): plasma potential via dI/dV 3. [PR #813](https://github.com/PlasmaPy/PlasmaPy/pull/813): Langmuir & Diagnostic Framework ## Minutes * fit functions to add * Gaussian * Gaussian + DC offset * Gaussian + Linear offset * Cauchy-Lorentz distribution * **Should first update Gaussian distribution in `plasmapy.formulary.distribution` and add the Cauchy distribution.** * `find_plasma_potential_didv()` * it's difficult to attribute an uncertainty with the `vp` calculation since we don't have an analytical model to fit to the curve * a proposed "uncertainty" would use the peak width at some prominence level * Should this prominence be a fixed value, a level based on the signal-to-noise ratio, and/or an input argument? * [Steve's suggestion] use the prominence level equivalent to 1 sigma of a Gaussian * [Steve] prefers using the FWHM as the default width * Should report the prominence of the peak, but this does not encompass all the info * this gives the height above the baseline * it does not factor in the noise level of the signal * **for now we should stick with the peak prominence and open an issue to construct a metric that considers the signal noise** * possible peak fitters * Gaussian * Lorentzian * piecewise linear * piecewise Exponential+Linear * As an option, have `find_plasma_potential_didv()` find `Te` on request ```python def find_plasma_potential_didv(get_Te=false): ... # calculate didv didv_arr = ... didv_xpart = ... # find vp vp = .... if get_Te: # crop data for fit vp_index = ... didv_sub = didv_arr[start:vp_index] vsub = didv_xarr[start:vp_index] te_resutls = find_electron_temp_didv(vsub, didv_sub) return vp_results, te_results def find_electron_temp_didv(vdata, didvdata): # calc te by fitting return te_results ```