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NAME: b1_status_crib.pro SYNTAX: PURPOSE: Create tplot variables pertaining to EFW burst existence INPUT: OUTPUT: KEYWORDS: PROCEDURE: .run b1_status_crib HISTORY: Created by Kris Kersten, kris.kersten@gmail.com VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/b1_status_crib.pro $
(See general/missions/rbsp/efw/examples/b1_status_crib.pro)
NAME: mini_gem_crib.pro SYNTAX: PURPOSE: EFW crib sheet for the mini-GEM meeting at Fall AGU 2012. Loads a bunch of useful data products KEYWORDS: HISTORY: Aaron Breneman, UMN, Dec 2012 (awbrenem@gmail.com)
(See general/missions/rbsp/efw/examples/mini_gem_crib.pro)
NAME: rbsp_boom_directions_crib SYNTAX: PURPOSE: find the pointing direction of the EFW booms in GSE coord INPUT: times -> array of times to find boom directions for probe -> 'a' or 'b' OUTPUT: tplot variables of each antenna direction in GSE ['vecu_gse','vecv_gse','vecw_gse'] KEYWORDS: HISTORY: Written by Aaron W Breneman 05/12/2014 VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_boom_directions_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_boom_directions_crib.pro)
NAME: rbsp_efw_burst_fa_rotate_crib SYNTAX: PURPOSE: Rotate RBSP EFW burst data to field-aligned coordinates INPUT: OUTPUT: KEYWORDS: HISTORY: Created by Aaron W Breneman, Univ. Minnesota 4/10/2014 VERSION: $LastChangedBy: aaronbreneman $ $LastChangedDate: 2020-09-11 13:35:30 -0700 (Fri, 11 Sep 2020) $ $LastChangedRevision: 29139 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_burst_fa_rotate_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_burst_fa_rotate_crib.pro)
NAME: rbsp_efw_convection_efield_crib SYNTAX: PURPOSE: Calculate RBSP convection electric field and velocity INPUT: OUTPUT: KEYWORDS: HISTORY: Written by Aaron W Breneman, July 2016. Based on Scott Thaller's crib VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_convection_efield_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_convection_efield_crib.pro)
***************************************************************************************** FUNCTION : rbsp_efw_DCfield_removal_crib PURPOSE : Subtract off DC magnetic field from Bw values. Saves as new tplot files REQUIRES: Need: SSL THEMIS software and IDL Geopack DLM both found at http://themis.ssl.berkeley.edu/software.shtml INPUT: probe -> 'a' or 'b' model -> Any of the Tsyganenko models or 'igrf'. Defaults to 't96' ql -> set to load quicklook EMFISIS data cadence -> cadence of EMFISIS data. 'hires', '4sec', '1sec' nodelete -> don't delete various tplot variables upon exit _extra --> useful keywords are: no_spice_load no_rbsp_efw_init EXAMPLES: Produces the following variables (ex for magname = 'rbspa_mag_gsm', model='t96') rbspa_mag_gsm_t96 rbspa_mag_gsm_t96_dif If the model is not t89 then produces: rbspa_mag_gsm_t96_wind rbspa_mag_gsm_t96_wind_dif rbspa_mag_gsm_t96_ace rbspa_mag_gsm_t96_ace_dif rbspa_mag_gsm_t96_omni rbspa_mag_gsm_t96_omni_dif NOTES: ruthlessly pilfered from THEMIS crib sheets Subtracts off Tsyganenko values using input from ACE, Wind and OMNI, as well as user defined input. CREATED: 2012/12/12 CREATED BY: Aaron W. Breneman LAST MODIFIED: 08/26/2012 v1.0.0 - major update. Much simplified MODIFIED BY: AWB *****************************************************************************************
(See general/missions/rbsp/efw/examples/rbsp_efw_dcfield_removal_crib.pro)
NAME: rbsp_efw_edotb_to_zero_crib.pro PURPOSE: Crib sheet to calculate the RBSP spin-axis Efield (short boom) under the assumption that E*B=0. CALLING SEQUENCE: rbsp_efw_edotb_to_zero_crib,'2014-01-01','a' INPUT: date: e.g. '2014-01-01' probe: 'a' or 'b' KEYWORDS: noremove - Don't remove ExMGSE (spinaxis) values when By/Bx>3.732 or Bz/Bx>3.732 anglemin --> Min allowable angle b/t spinplane and Bo. Defaults to 15 deg Smaller angles will lead to less removed data, but can result in larger errors due to division by small numbers OUTPUT: tplot variables of the spinfit, MGSE electric field with xMGSE calculated assuming E*B=0 NOTES: Bad E*B=0 data are removed Spin axis values calculated from E*B=0 as Ex = -1*(EyBy + EzBz)/Bx The ratios By/Bx and Bz/Bx can fluctuate wildly when Bx gets too small. Therefore we require that these ratios are less than a certain size (i.e. sufficiently big Bx). The standard (from Cluster) is to assume that the angle between any of the spinplane directions (MGSE y and z in this case) and Bo is greater than 15 degrees. delta = angle(Bz, Bo) > 15 epsilon = angle(By, Bo) > 15 gamma = angle(Bx, Bo) < 75 Writing out the dot products we get: cos(delta) = Bz/Bo cos(epsilon) = By/Bo cos(gamma) = Bx/Bo We can rearrange these as: By/Bx = cos(epsilon)/cos(gamma) Bz/Bx = cos(delta)/cos(gamma) To find the max value of these ratios let epsilon = 15 deg, delta = 15, gamma = 75 deg. By/Bx = 3.732 Bz/Bx = 3.732 HISTORY: Written by Aaron W Breneman (UMN) - 2013-06-19 $LastChangedBy: aaronbreneman $ $LastChangedDate: 2020-09-11 13:33:33 -0700 (Fri, 11 Sep 2020) $ $LastChangedRevision: 29137 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_edotb_to_zero_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_edotb_to_zero_crib.pro)
NAME: rbsp_efw_position_velocity_crib.pro PURPOSE: Loads and plots RBSP (Van Allen probes) position and velocity related data CALLING SEQUENCE: timespan,'2014-01-01' rbsp_efw_position_velocity_crib INPUT: KEYWORDS: probe = set to specify to load only "a" or "b" other than both. no_spice_load -> set if you've already loaded the spice kernels noplot -> set to avoid tplotting notrace -> skip the ttrace2equator call. This takes a lot of computational time nospinaxis_calcs -> skip the part that loads the spinaxis pointing direction. This can be problematic on certain dates. Only set if you don't need the spinaxis direction or the sc velocity in mGSE coord _extra --> possible useful extra keywords include: no_spice_load no_rbsp_efw_init OUTPUT: various tplot variables HISTORY: Written by Aaron Breneman, UMN, Dec 2012 email: awbrenem@gmail.com REQUIRED: Need to have the SPICE ICY software package installed $LastChangedBy: aaronbreneman $ $LastChangedDate: 2020-09-11 13:32:39 -0700 (Fri, 11 Sep 2020) $ $LastChangedRevision: 29136 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_position_velocity_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_position_velocity_crib.pro)
NAME: rbsp_efw_poynting_flux_crib.pro SYNTAX: PURPOSE: Crib sheet for calling rbsp_poynting_flux.pro, which creates Poynting flux tplot variables (including spectra) from EFW and EMFISIS data in various coord systems. Plots results INPUT: OUTPUT: KEYWORDS: PROCEDURE: load EMFISIS data in GSE. Transform EMFISIS GSE -> MGSE Load EFW despun waveform data in MGSE Call Poynting flux program HISTORY: Created by Aaron W Breneman, UMN awbrenem@gmail.com VERSION: $LastChangedBy: aaronbreneman $ $LastChangedDate: 2020-09-11 13:39:04 -0700 (Fri, 11 Sep 2020) $ $LastChangedRevision: 29141 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_poynting_flux_burst_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_poynting_flux_burst_crib.pro)
NAME: rbsp_efw_poynting_flux_survey_crib.pro SYNTAX: PURPOSE: Crib sheet for creating Poynting flux tplot variables from EFW and EMFISIS survey data. This is called by the program rbsp_efw_make_pflux.pro, but can be used independently. INPUT: smoothing -> period (sec) to smooth over detrending -> period (sec) to detrend over cadence_mag -> '1sec','4sec','hires' spinfit -> spinfit the Efield data? Otherwise uses the 32 S/s MGSE data OUTPUT: tplot variables of Poynting flux in various coord systems KEYWORDS: NOTES: The burst and tt0 and tt1 keywords were added (by Aaron) to test the results of this crib sheet with rbsp_poynting_flux.pro. They compare almost identically for a test chorus event. (see aaron_scott_pflux_comparison.pro) HISTORY: Adapted from Scott Thaller's Poynting flux crib by Aaron Breneman VERSION: $LastChangedBy: aaronbreneman $ $LastChangedDate: 2020-09-11 13:39:41 -0700 (Fri, 11 Sep 2020) $ $LastChangedRevision: 29143 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_poynting_flux_crib_scott.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_poynting_flux_crib_scott.pro)
NAME: rbsp_efw_poynting_flux_survey_crib.pro SYNTAX: PURPOSE: Crib sheet for creating Poynting flux tplot variables from EFW and EMFISIS data. This is called by the program rbsp_efw_make_pflux.pro, but can be used independently. INPUT: smoothing -> period (sec) to smooth over detrending -> period (sec) to detrend over cadence_mag -> '1sec','4sec','hires' spinfit -> spinfit the Efield data? Otherwise uses the 32 S/s MGSE data OUTPUT: tplot variables of Poynting flux in various coord systems KEYWORDS: NOTES: The burst and tt0 and tt1 keywords were added (by Aaron) to test the results of this crib sheet with rbsp_poynting_flux.pro. They compare almost identically for a test chorus event. (see aaron_scott_pflux_comparison.pro) HISTORY: Adapted from Scott Thaller's Poynting flux crib by Aaron Breneman VERSION: $LastChangedBy: aaronbreneman $ $LastChangedDate: 2020-09-11 13:39:29 -0700 (Fri, 11 Sep 2020) $ $LastChangedRevision: 29142 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_poynting_flux_survey_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_poynting_flux_survey_crib.pro)
NAME: rbsp_efw_spec_crib.pro SYNTAX: PURPOSE: Create tplot variables pertaining to RBSP EFW spectral products INPUT: OUTPUT:; SPEC returns 7 channels, with nominal data selection: SPEC0: E12AC SPEC1: E56AC SPEC2: SCMpar SPEC3: SCMperp SPEC4: SCMW SPEC5: V1AC SPEC6: V2AC KEYWORDS: HISTORY: ; Kris Kersten, UMN, June 2012 (kris.kersten@gmail.com) Modified by Aaron Breneman, UMN, Dec 2012 (awbrenem@gmail.com) VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_spec_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_spec_crib.pro)
NAME: rbsp_efw_spinfit_crib.pro SYNTAX: PURPOSE: Crib sheet for crating EFW spinfit electric field in spinning spacecraft coord (DSC) INPUT: OUTPUT: KEYWORDS: HISTORY: Created by Jianbao Tao, SSL/UCB. VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_spinfit_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_spinfit_crib.pro)
NAME: rbsp_efw_spinfit_vxb_subtract_crib.pro PURPOSE: Create the vxb subtracted spinfit data product for EFW CALLING SEQUENCE: timespan,'2014-01-01' rbsp_efw_spinfit_vxb_crib,'a' INPUT: probe --> 'a' or 'b' KEYWORDS: ql -> select to load EMFISIS quicklook data. Defaults to hires L3 data but quicklook data are available sooner. qa -> select to load QA waveform data. Don't want to use this route for normal data processing. hiresl3 -> loads the EMFISIS high resolution 64 S/s L3 GSE data level -> Level of EMFISIS data. Options are: 'ql', 'l2', 'l3'. Defaults to EMFISIS L3 data boom_pair -> select the boom pair for the spinfitting. Any pair is acceptable no_reload -> use to not reload any of the base data. Useful if you want to run this crib sheet multiple times for different boom pairs. _extra --> possible useful keywords include: no_spice_load OUTPUT: tplot variables of spinfit, vxb subtracted electric field NOTES: If doing spinfit on pairs 12, 34, we load the "esvy" waveform. This gives us the Efield array (rbsp?_efw_esvy) as [[E12],[E34],[E56]]. This array is inputted into rbsp_spinfit.pro and the plane_dim is set to 0,1 depending on which component (E12 or E34) you want to spinfit off of. ** For pairs other than 12, 34, 56, we have to load "vsvy" waveform and construct the components manually. The first element of this array (normally E12) will be replaced with the new component. For ex, for pair=24, the array (rbsp?_efw_esvy) will be [[E24],[E34],[E56]]. We'll then set plane_dim to zero to use this component. HISTORY: Written by Aaron W Breneman University of Minnesota 2013-04-16 $LastChangedBy: aaronbreneman $ $LastChangedDate: 2020-10-15 10:55:25 -0700 (Thu, 15 Oct 2020) $ $LastChangedRevision: 29256 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_spinfit_vxb_subtract_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_spinfit_vxb_subtract_crib.pro)
NAME: rbsp_efw_summary_crib.pro SYNTAX: PURPOSE: Create tplot variables pertaining to EFW summary data (waveform, spec, xspec, filterbank) INPUT: OUTPUT: KEYWORDS: HISTORY: Kris Kersten, UMN, June 2012 (email: kris.kersten@gmail.com) VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_summary_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_summary_crib.pro)
NAME: rbsp_efw_vxb_subtract_crib.pro PURPOSE: Creates vxB subtracted tplot variables for the 32 S/s EFW efield data ****NOTE: IF YOU DON'T NEED THE FULL 32 S/s RESOLUTION THEN CONSIDER USING ****rbsp_efw_spinfit_vxb_subtract_crib.pro ****THE DATA WILL BE AT SPINPERIOD CADENCE BUT WILL BE CLEANER WARNING!!! RESULTS ARE PRELIMINARY. DO NOT PUBLISH OR PRESENT THESE RESULTS WITHOUT FIRST CONSULTING THE EFW PI JOHN WYGANT <wygan001@umn.edu> CALLING SEQUENCE: timespan,'2014-01-01' rbsp_efw_vxb_subtract_crib,'a' INPUT: 'a' or 'b' for probe KEYWORDS: ql -> use EMFISIS quicklook UVW data instead of 4sec GSE L3. This will be despun and spinfit. This has the advantage of not having to wait for the EMFISIS L3 data set to be produced. Note: Defaults to 4-sec EMFISIS data in GSE. This is actually superior to the hires GSE data b/c it doesn't have spurious data spikes. It works about the same as JBT's method of despinning and then spinfitting the EMFISIS quicklook UVW data. hires -> use EMFISIS hires L3 GSE data instead of 4sec GSE L3. qa -> load the QA testing L1 EFW data instead of the usual L1 data OUTPUT: HISTORY: Created by Aaron Breneman, UMN, Dec 2012 email: awbrenem@gmail.com REQUIRES: THEMIS TDAS software http://themis.ssl.berkeley.edu/software.shtml as well as SPICE software $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_vxb_subtract_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_vxb_subtract_crib.pro)
NAME: rbsp_efw_waveform_crib SYNTAX: PURPOSE: Loads and plots RBSP (Van Allen probes) waveform data KEYWORDS: HISTORY: Kris Kersten, UMN, June 2012 (kris.kersten@gmail.com) Modified by Aaron Breneman, UMN, Dec 2012 (awbrenem@gmail.com) VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_waveform_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_waveform_crib.pro)
NAME: rbsp_efw_xspec_crib.pro SYNTAX: PURPOSE: Create tplot variables pertaining to the EFW cross-spectral product INPUT: OUTPUT: KEYWORDS: PROCEDURE: .run b1_status_crib HISTORY: Kris Kersten, UMN, June 2012 (kris.kersten@gmail.com) Modified by Aaron Breneman, UMN, Dec 2012 (awbrenem@gmail.com) VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_efw_xspec_crib.pro $
(See general/missions/rbsp/efw/examples/rbsp_efw_xspec_crib.pro)
NAME: rbsp_load_collection SYNTAX: PURPOSE: Load collection time <remote_dir>/burst_selection/rbspx_b1_rec.dat. INPUT: cts, out, dblarr[n,2], req. Collection times in UT second. probe, in, 'a' or 'b', opt. Default is 'a'. OUTPUT: KEYWORDS: HISTORY: 2014-04-09, created by Sheng Tian, UMN VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_load_collection.pro $
(See general/missions/rbsp/efw/examples/rbsp_load_collection.pro)
Type: procedure. Purpose: Load contact time <remote_dir>/MOC_data_products/RBSPX/contact_plan'. Parameters: cts, out, dblarr[n,2], req. Contact times in UT second. probe, in, 'a' or 'b', opt. Default is 'a'. Keywords: none. Notes: none. Dependence: tdas. History: 2014-04-09, Sheng Tian, create.
(See general/missions/rbsp/efw/examples/rbsp_load_contact.pro)
Deprecated, 2020-04-13, jmm NAME: rbsp_mageis_example_crib.pro SYNTAX: PURPOSE: Crib sheet showing how to load MagEIS data INPUT: OUTPUT: KEYWORDS: HISTORY: Created by Aaron Breneman VERSION: $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/rbsp_mageis_example_crib_old.pro $
(See general/missions/rbsp/efw/examples/rbsp_mageis_example_crib_old.pro)
NAME:twavpol PURPOSE:To perform polarisation analysis of three orthogonal component time series data, using tplot variables. EXAMPLE: twavpol,'in_data',prefix='in_data',freqline=fl INPUTS: tvarname: the name of the tplot variable upon which it will operate prefix(optional): the prefix to be assigned to the tplot variables that will be output, defaults to tvarname Subroutine assumes data are in righthanded fieldaligned coordinate system with Z pointing the direction of the ambient magnetic field. Keywords: nopfft(optional) = Number of points in FFT steplength(optional) = The amount of overlap between successive FFT intervals bin_freq (optional): No. of bins in frequency domain OUTPUTS: error(optional): named variable in which to return the error state of this procedure call. 1 = success, 0 = failure freqline(optional): assign a named variable to this keyword to store the frequencies of each y-index timeline(optional): assign a named variable to this keyword to store the times of each x-index The program outputs five spectral results derived from the fourier transform of the covariance matrix (spectral matrix) This version stores these outputs as tplot variables with the specified prefix These are follows: Wave power: On a linear scale, at this stage no units Degree of Polarisation: This is similar to a measure of coherency between the input signals, however unlike coherency it is invariant under coordinate transformation and can detect pure state waves which may exist in one channel only.100% indicates a pure state wave. Less than 70% indicates noise. For more information see J. C. Samson and J. V. Olson 'Some comments on the description of the polarization states of waves' Geophys. J. R. Astr. Soc. (1980) v61 115-130 Wavenormal Angle: The angle between the direction of minimum variance calculated from the complex off diagonal elements of the spectral matrix and the Z direction of the input ac field data. for magnetic field data in field aligned coordinates this is the wavenormal angle assuming a plane wave. See: Means, J. D. (1972), Use of the three-dimensional covariance matrix in analyzing the polarization properties of plane waves, J. Geophys. Res., 77(28), 5551-5559, doi:10.1029/JA077i028p05551. Ellipticity: The ratio (minor axis)/(major axis) of the ellipse transcribed by the field variations of the components transverse to the Z direction (Samson and Olson, 1980). The sign indicates the direction of rotation of the field vector in the plane (cf. Means, (1972)). Negative signs refer to left-handed rotation about the Z direction. In the field aligned coordinate system these signs refer to plasma waves of left and right handed polarization. Helicity:Similar to Ellipticity except defined in terms of the direction of minimum variance instead of Z. Stricltly the Helicity is defined in terms of the wavenormal direction or k. However since from single point observations the sense of k cannot be determined, helicity here is simply the ratio of the minor to major axis transverse to the minimum variance direction without sign. NOTES: 1. Although the input is in the form of a tplot variable, the output is currently in the form of arrays 2. -If one component is an order of magnitude or more greater than the other two then the polarisation results saturate and erroneously indicate high degrees of polarisation at all times and frequencies. 3. Time series should be eyeballed before running the program. For time series containing very rapid changes or spikes the usual problems with Fourier analysis arise. Care should be taken in evaluating degree of polarisation results. 4. For meaningful results there should be significant wave power at the frequency where the polarisation approaches 100%. Remembercomparing two straight lines yields 100% polarisation. $LastChangedBy: nikos $ $LastChangedDate: 2020-05-21 20:36:46 -0700 (Thu, 21 May 2020) $ $LastChangedRevision: 28720 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/general/missions/rbsp/efw/examples/twavpol_modified.pro $
(See general/missions/rbsp/efw/examples/twavpol_modified.pro)