pyrfu.pyrf

Generic routines to build, transform and analyse space plasma time series: time series construction, time conversions, coordinate systems, signal processing, wave analysis, multi-spacecraft methods and plasma parameters.

from pyrfu import pyrf

Time series construction

ts_scalar	Create a time series containing a 0th order tensor
ts_vec_xyz	Create a time series containing a 1st order tensor.
ts_tensor_xyz	Create a time series containing a 2nd order tensor.
ts_spectr	Create a time series containing a spectrum
ts_skymap	Creates a skymap of the distribution function.
ts_time	Creates time line in DataArray.
ts_append	Concatenate two time series along the time axis.
dist_append	Concatenate two distribution skymaps along the time axis.

Time series utilities

time_clip	Time clip the input (if time interval is TSeries clip between start and stop).
resample	Resample inp to the time line of ref.
t_eval	Evaluates the input time series at the target time.
start	Gives the first time of the time series.
end	Gives the last time of the time series in unix format.
extend_tint	Extends time interval.
calc_dt	Compute time step of the input time series.
calc_fs	Computes the sampling frequency of the input time series.
find_closest	Finds pairs that are closest to each other in two time series.
remove_repeated_points	Remove repeated elements in DataArray, Dataset or structure data.
date_str	Creates a string corresponding to time interval for output plot naming.

Time format conversions

cdfepoch2datetime64	Converts CDF epochs to numpy.datetime64 with nanosecond precision.
datetime2iso8601	Transforms datetime to TT2000 string format.
datetime642iso8601	Convert datetime64 in ns units to ISO 8601 time format .
datetime642ttns	Converts datetime64 to epoch_tt2000 (nanoseconds since J2000).
datetime642unix	Converts datetime64 in ns units to unix time.
iso86012datetime	Convert ISO 8601 time to datetime.
iso86012datetime64	Convert ISO8601 time format to datetime64 in ns units.
iso86012timevec	Convert ISO 8601 time string into time vector.
iso86012unix	Converts time in iso format to unix
timevec2iso8601	Convert time vector into ISO 8601 format YYYY-MM-DDThh:mm:ss.mmmuuunnn.
ttns2datetime64	Convert time in epoch_tt2000 (nanoseconds since J2000) to datetime64 in ns units.
unix2datetime64	Converts unix time to datetime64 in ns units.

Vector and tensor operations

dot	Compute dot product of two fields.
cross	Compute cross product of two fields.
norm	Computes the magnitude of the input field.
normalize	Normalizes the input field.
trace	Computes trace of the time series of 2nd order tensors.
dec_par_perp	Decomposes a vector into par/perp to B components.
cart2sph	Cartesian to spherical coordinate transform.
cart2sph_ts	Computes magnitude, theta and phi angle from column vector xyz (first column is x ....) theta is 0 at equator.
sph2cart	Transform spherical to cartesian coordinates
solid_angle	Calculates the solid angle of three vectors making up a triangle in a unit sphere with the sign taken into account.

Coordinate systems

cotrans	Coordinate transformation GE0/GEI/GSE/GSM/SM/MAG as described in [R93910b019a51-1]
gse2gsm	Converts GSE to GSM.
convert_fac	Transform to a field-aligned coordinate (FAC) system.
new_xyz	Transform the input field to the new frame.
mva	Compute the minimum variance frame.
mva_gui	GUI to interactively perform minimum variance analysis (MVA) on time series data by selecting the time interval to apply MVA on.
mean	Put inp into mean field coordinates defined by position vector r and magnetic field b if earth magnetic dipole axis z is given then uses another algorithm (good for auroral passages).
eb_nrf	Find E and B in MP system given B and MP normal vector.
l_shell	Compute spacecraft position L Shell for a dipole magnetic field according to IGRF.

Filtering and signal processing

filt	Filters input quantity.
lowpass	Filter the data through low or highpass filter with max frequency f_cut and subtract from the original.
medfilt	Applies a median filter over npts points to inp.
movmean	Computes running average of the inp over window_size points.
mean_field	Estimate the mean and wave fields.
ts_convolve	Compute the convolution of a time series of N-dimensional data with a N-dimensional kernel.
integrate	Integrate time series.
gradient	Computes time derivative of the input variable.
sliding_derivative	Compute the sliding time derivative of a time series using central differences.
autocorr	Compute the autocorrelation function.
corr_deriv	Correlate the derivatives of two time series

Spectral and wave analysis

psd	Estimate power spectral density using Welch's method.
wave_fft	Short-Time Fourier Transform.
wavelet	Computes wavelet spectrogram based on fast FFT algorithm.
compress_cwt	Compress the wavelet transform averaging over blocks of nc time steps.
ebsp	Calculates wavelet spectra of E&B and Poynting flux using wavelets (Morlet wavelet).
wavepolarize_means	Analysis the polarization of magnetic wave using "means" method
poynting_flux	Estimates Poynting flux at electric field sampling as
match_phibe_dir	Get propagation direction by matching dBpar and "phi".
match_phibe_v	Get propagation velocity by matching dBpar and phi.

Turbulence and intermittency

increments	Returns the increments of a time series.
struct_func	Returns the structure function of a time series
pvi	Returns the Partial Variance of Increments (PVI) of a time series.

Multi-spacecraft methods

avg_4sc	Computes the input quantity at the center of mass of the MMS tetrahedron.
nanavg_4sc	Average data from 4 spacecrafts while ignoring NaN values.
c_4_k	Calculates reciprocal vectors in barycentric coordinates.
c_4_grad	Calculate gradient of physical field using 4 spacecraft technique in [Ra4e11c05c7b9-2] [Ra4e11c05c7b9-3].
c_4_j	Calculate the current density using the four spacecraft technique.
c_4_v	Calculates velocity or time shift of discontinuity as in [Rb7b35f387832-6].
st_diff	Computes velocity of the structure using spatio-temporal derivative method [Rfdd5e57aa6d8-13] [Rfdd5e57aa6d8-14] as
pid_4sc	Compute Pi-D term using definition of [R8b551134d697-1] as :
pvi_4sc	Compute the Partial Variance of Increments (PVI) using the definition in [R64a80c2671ce-1] as

Plasma parameters

plasma_calc	Computes plasma parameters including characteristic length and time scales.
iplasma_calc	Interactive function to calcute plasma paramters.
plasma_beta	Computes plasma beta at magnetic field sampling
dynamic_press	Computes dynamic pressure.
e_vxb	Computes the convection electric field \(V\times B\) (default) or the \(E\times B/|B|^{2}\) drift velocity (flag="exb").
edb	Compute Ez under assumption \(\mathbf{E}.\mathbf{B}=0\) or \(\mathbf{E}.\mathbf{B} \approx 0\)
vht	Estimate velocity of the De Hoffman-Teller frame from the velocity estimate the electric field eht=-vht x b
estimate	Estimate values for some everyday stuff.

Pressure tensor, anisotropy and agyrotropy

pres_anis	Compute pressure anisotropy factor:
anisotropy_thresholds	Compute the thresholds for temperature anisotropy instabilities based on plasma species and growth rate.
calc_ag	Compute Che's agyrotropy coefficient.
calc_agyro	Compute agyrotropy coefficient as
calc_dng	Computes Aunai's agyrotropy coefficient.
calc_sqrtq	Computes agyrotropy coefficient as in [R397062005517-1]

Velocity distribution functions

average_vdf	Time averages the velocity distribution functions over n_pts in time.
int_sph_dist	Integrate a spherical distribution function to a line/plane.

Shocks and boundaries

shock_normal	Calculates shock normals with different methods.
shock_parameters	Calculate shock related plasma parameters.
magnetosphere	Returns the location of magnetopause.

Statistics and histograms

histogram	Computes 1D histogram of the inp with bins bins
histogram2d	Computes 2d histogram of inp2 vs inp1 with nbins number of bins.
brazil	Computes 2D histogram and PDF (Brazil plot style) for plasma data.
mean_bins	Computes mean of values of y corresponding to bins of x.
median_bins	Computes median of values of y corresponding to bins of x
optimize_nbins_1d	Estimates the number of bins for 1d histogram that minimizes the risk function in [R10e5c351ffb9-1] , obtained by direct decomposition of the MISE following the method described in [R10e5c351ffb9-2] .
optimize_nbins_2d	Estimates the number of bins for 2d histogram that minimizes the risk function in [R0adc3d7e4a0c-1] , obtained by direct decomposition of the MISE following the method described in [R0adc3d7e4a0c-2] .
waverage	Computes weighted average.

Data files and external data

read_cdf	Reads a .cdf file and returns a dictionary with the fields contained in the file.
get_omni_data	Downloads OMNI data.