Analysator supported data reducers and vlasiator variables
This documents is intended as a helpful but incomplete reference for vlasiator outputs and post-processing data reducers supported by Analysator
Reading variables from .vlsv files
Analysator supports reading multiple different types of variables:
MPIgrid variables
FSgrid variables
variables directly available in the data files
variables generated via receipes from the data file variables (named, somewhat incorrectly, datareducers)
Vlasiator variable naming scheme
In Vlasiator versions before V5, variables were always saved on the DCCRG/MPI/Vlasov grid, and as such, only a single naming scheme was required. With the introduction of Vlasiator V5, variables could also be saved on the FSgrid. When the ionosphere grid was be implemented, that can also be saved to on its own grid. To differentiate between the different grids, a naming scheme was introduced where a prefix defines the grid type:
No prefix: old pre-V5 data
prefix
vg_: Vlasov/MPI/DCCRG gridprefix
fg_: fieldsolver/FSgridprefix
ig_: ionosphere grid
Multipop naming (version 4 onwards)
Some variables are directly connected to a given particle species, with the variable name having a
particle species prefix. For example: proton/rho or proton/vg_rho for V4 and V5 outputs
respectively. Note that multipop outputs are always on the Vlasov grid, but still have the vg_
prefix after the particle species name. Some variable such as rho and blocks which are
directly connected to particle species are availabe without the population identifier in datafiles
from version 3 and earlier, assuming the species to be protons.
Vlasiator variable correspondences
The below tables list variable names used in different versions of Vlasiator proper (updated: 3.6.2021). A blank entry in a corresponding column indicates this variable is not available. Some debugging variables such as field derivatives have been omitted from the table.
FSgrid variables |
Corresponding Vlasov grid variable in older versions |
|---|---|
fg_b |
B |
fg_b_background |
background_B |
fg_b_perturbed |
perturbed_B |
fg_b_vol |
B_vol |
fg_e |
E |
fg_e_hall_?? |
EXHALL_???_??? |
fg_e_vol |
E_vol |
fg_rhom |
Rhom |
fg_rhoq |
Rhoq |
fg_v |
V |
fg_pressure |
Pressure |
fg_maxdt_fieldsolver |
max_fields_dt |
fg_rank |
FSgrid_rank |
fg_amr_level |
|
fg_boundarytype |
FSgrid_boundaryType |
fg_boundarylayer |
Boundary_layerx |
V5 Vlasov grid variables |
Older Vlasov grid variables |
|---|---|
vg_rhom |
Rhom |
vg_rhoq |
Rhoq |
vg_v |
V |
vg_pressure |
Pressure |
Blocks |
|
vg_b_vol |
B_vol |
vg_b_background_vol |
BGB_vol |
vg_b_perturbed_vol |
PERB_vol |
E |
|
vg_e_vol |
E_vol |
vg_e_gradpe |
EGRADPE |
vg_f_saved |
fSaved |
vg_maxdt_acceleration |
max_v_dt |
vg_maxdt_translation |
max_r_dt |
vg_rank |
MPI_rank |
vg_loadbalance_weight |
LB_weight |
vg_boundarytype |
Boundary_type |
vg_boundarylayer |
Boundary_layer |
Per-population variables |
Older per-population variables |
Older pre-multipop variables |
|---|---|---|
populations/vg_rho |
populations/rho |
|
populations/vg_v |
populations/V |
|
populations/vg_rho_thermal |
populations/RhoNonBackstream |
|
populations/vg_rho_nonthermal |
populations/RhoBackstream |
|
populations/vg_v_thermal |
populations/VNonBackstream |
|
populations/vg_v_nonthermal |
populations/VBackstream |
|
populations/vg_effectivesparsitythreshold |
populations/EffectiveSparsityThreshold |
|
populations/vg_rho_loss_adjust |
populations/rho_loss_adjust |
|
populations/vg_energydensity |
populations/EnergyDensity |
|
populations/vg_precipitationdifferentialflux |
populations/PrecipitationDiffFlux |
|
populations/vg_maxdt_acceleration |
populations/MaxVdt |
|
populations/vg_maxdt_translation |
populations/MaxRdt |
|
populations/vg_blocks |
populations/Blocks |
|
populations/vg_acceleration_subcycles |
populations/acc_subcycles |
|
populations/vg_ptensor_diagonal |
populations/PTensorDiagonal |
|
populations/vg_ptensor_offdiagonal |
populations/PTensorOffDiagonal |
|
populations/vg_ptensor_nonthermal_diagonal |
populations/PTensorBackstreamDiagonal |
|
populations/vg_ptensor_nonthermal_offdiagonal |
populations/PTensorBackstreamOffDiagonal |
|
populations/vg_ptensor_thermal_diagonal |
populations/PTensorNonBackstreamDiagonal |
|
populations/vg_ptensor_thermal_offdiagonal |
populations/PTensorNonBackstreamOffDiagonal |
Analysator datareducers
Post-processed derived variables (called somewhat mistakenly datareducers) are available in analysator. One limitation is that in current versions of analysator (as of March 2022) all datareducers require Vlasov grid variables as they work with CellID lists. Also, datareducers do not support spatial or temporal derivatives. However, both use of FSgrid variables and spatial and temporal derivatives in plotting routines is possible via expressions and external functions as called by plot_colormap and other such plotting routines (see also plot_helpers.py).
The up-to-date list of datareducers can always be found in pyVlsv/reduction.py
List of datareducers for Vlasiator versions 1…4
Note: If several populations exist for a v4 multipop run, temperature reducers are incorrect. If the value is available directly instead of as a datareducer, that name is listed instead in parathentheses. If it is available through multipop datareducers, it is shown with “mpop”.
v5 datareducer |
v1…4 datareducer |
explanation |
|---|---|---|
(vg_v) |
v |
velocity |
vg_vms |
vms |
magnetosonic speed |
vg_vs |
vs |
sound speed |
vg_va |
va |
Alfvén speed |
vg_ma |
ma |
Alfvén Mach number |
vg_mms |
mms |
magnetosonic Mach number |
vg_di |
di |
Ion inertial length |
vg_v_parallel |
vparallel |
V parallel to B |
vg_v_perpendicular |
vperpendicular |
V perpendicular to B |
mpop |
vparallelbackstream |
non-thermal proton V parallel to B |
mpop |
vperpendicularbackstream |
non-thermal proton V perpendicular to B |
mpop |
vparallelnonbackstream |
thermal proton V parallel to B |
mpop |
vperpendicularnonbackstream |
thermal proton V perpendicular to B |
vg_e_parallel |
eparallel |
E component parallel to B |
vg_e_perpendicular |
eperpendicular |
E component perpendicular to B |
vg_pdyn |
pdyn |
dynamic pressure |
vg_pdynx |
pdynx |
dynamic pressure from only x-directional velocity |
vg_poynting |
poynting |
Poynting vector |
n/a |
firstadiabatic |
mean first adiabatic invariant |
vg_egradpe_parallel |
n/a |
Electric field electron pressure gradient term parallel to B |
vg_egradpe_perpendicular |
n/a |
Electric field electron pressure gradient term perpendicular to B |
vg_restart_v |
restart_v |
estimate V from a restart file |
vg_restart_rho |
restart_rho |
estimate particle number density from a restart file |
vg_restart_rhom |
restart_rhom |
estimate mass density from a restart file |
vg_restart_rhoq |
restart_rhoq |
estimate charge density from a restart file |
List of per-population datareducers for Vlasiator versions 4 and 5.
For these multipop datareducers, replace pop with required population name. If pop/ is
omitted, a sum over per-population values is provided.
v5 datareducer |
v4 datareducer |
explanation |
|---|---|---|
pop/vg_rhom |
pop/rhom |
mass density |
pop/vg_rhoq |
pop/rhoq |
charge density |
pop/vg_pdyn |
pop/pdyn |
dynamic pressure |
pop/vg_pdynx |
pop/pdynx |
dynamic pressure from only x-directional velocity |
pop/vg_v_parallel |
pop/vparallel |
V parallel to B |
pop/vg_v_perpendicular |
pop/vperpendicular |
V perpendicular to B |
pop/vg_v_parallel_nonthermal |
pop/vparallelbackstream |
non-thermal V parallel to B |
pop/vg_v_perpendicular_nonthermal |
pop/vperpendicularbackstream |
non-thermal V perpendicular to B |
pop/vg_v_parallel_thermal |
pop/vparallelnonbackstream |
thermal V parallel to B |
pop/vg_v_perpendicular_thermal |
pop/vperpendicularnonbackstream |
thermal V perpendicular to B |
pop/vg_thermalvelocity |
pop/thermalvelocity |
estimate of thermal velocity |
pop/vg_larmor |
pop/larmor |
estimate of representative Larmor radius |
pop/vg_firstadiabatic |
pop/firstadiabatic |
estimate of first adiabatic invariant (old!) |
pop/vg_gyroperiod |
pop/gyroperiod |
gyroperiod |
pop/vg_plasmaperiod |
pop/plasmaperiod |
plasma period |
pop/vg_precipitationintegralenergyflux |
n/a |
Integral energy flux of precipitating particles estimate (several energy channels) |
pop/vg_precipitationmeanenergy |
n/a |
Mean energy of channel for precipitating particle fluxes |
pop/vg_pressure |
pop/pressure |
pressure |
pop/vg_ptensor |
pop/ptensor |
pressure tensor |
pop/vg_ptensor_rotated |
pop/ptensorrotated |
pressure tensor rotated to align with B |
pop/vg_p_parallel |
pop/pparallel |
pressure parallel to B |
pop/vg_p_perpendicular |
pop/pperpendicular |
pressure perpendicular to B |
pop/vg_p_anisotropy |
pop/pperpoverpar |
ratio of perpendicular pressure to parallel pressure |
pop/vg_p_nonthermal |
pop/pbackstream |
pressure due to non-thermal particles |
pop/vg_ptensor_nonthermal |
pop/ptensorbackstream |
pressure tensor due to non-thermal particles |
pop/vg_ptensor_rotated_nonthermal |
pop/ptensorrotatedbackstream |
pressure tensor due to non-thermal particles rotated to align with B |
pop/vg_p_parallel_nonthermal |
pop/pparallelbackstream |
pressure component due to non-thermal particles parallel to B |
pop/vg_p_perpendicular_nonthermal |
pop/pperpendicularbackstream |
pressure component due to non-thermal particles perpendicular to B |
pop/vg_p_anisotropy_nonthermal |
pop/pperpoverparbackstream |
ratio of perpendicular pressure to parallel pressure for non-thermal particles |
pop/vg_p_thermal |
pop/pnonbackstream |
pressure due to thermal particles |
pop/vg_ptensor_thermal |
pop/ptensornonbackstream |
pressure tensor due to thermal particles |
pop/vg_ptensor_rotated_thermal |
pop/ptensorrotatednonbackstream |
pressure tensor due to thermal particles rotated to align with B |
pop/vg_p_parallel_thermal |
pop/pparallelnonbackstream |
pressure component due to thermal particles parallel to B |
pop/vg_p_perpendicular_thermal |
pop/pperpendicularnonbackstream |
pressure component due to thermal particles perpendicular to B |
pop/vg_p_anisotropy_thermal |
pop/pperpoverparnonbackstream |
ratio of perpendicular pressure to parallel pressure for thermal particles |
pop/vg_temperature |
pop/temperature |
temperature |
pop/vg_ttensor |
pop/ttensor |
temperature tensor |
pop/vg_ttensor_rotated |
pop/ttensorrotated |
temperature tensor rotated to align with B |
pop/vg_t_parallel |
pop/tparallel |
temperature parallel to B |
pop/vg_t_perpendicular |
pop/tperpendicular |
temperature perpendicular to B |
pop/vg_t_nonthermal |
pop/tbackstream |
temperature of non-thermal particles |
pop/vg_ttensor_nonthermal |
pop/ttensorbackstream |
temperature tensor of non-thermal particles |
pop/vg_ttensor_rotated_nonthermal |
pop/ttensorrotatedbackstream |
temperature tensor of non-thermal particles rotated to align with B |
pop/vg_t_parallel_nonthermal |
pop/tparallelbackstream |
temperature component of non-thermal particles parallel to B |
pop/vg_t_perpendicular_nonthermal |
pop/tperpendicularbackstream |
temperature component of non-thermal particles perpendicular to B |
pop/vg_t_thermal |
pop/tnonbackstream |
temperature of thermal particles |
pop/vg_ttensor_thermal |
pop/ttensornonbackstream |
temperature tensor of thermal particles |
pop/vg_ttensor_rotated_thermal |
pop/ttensorrotatednonbackstream |
temperature temperature tensor of thermal particles rotated to align with B |
pop/vg_t_parallel_thermal |
pop/tparallelnonbackstream |
temperature component of thermal particles parallel to B |
pop/vg_t_perpendicular_thermal |
pop/tperpendicularnonbackstream |
temperature component of thermal particles perpendicular to B |
pop/vg_t_anisotropy |
pop/tperpoverpar |
ratio of perpendicular temperature to parallel temperature |
pop/vg_t_anisotropy_nonthermal |
pop/tperpoverparbackstream |
ratio of perpendicular temperature to parallel temperature for non-thermal particles |
pop/vg_t_anisotropy_thermal |
pop/tperpoverparnonbackstream |
ratio of perpendicular temperature to parallel temperature for thermal particles |
pop/vg_agyrotropy |
pop/agyrotropy |
agyrotropy (according to Swisdak 2016) |
pop/vg_agyrotropy_nonthermal |
pop/agyrotropybackstream |
agyrotropy for non-thermal particles |
pop/vg_agyrotropy_thermal |
pop/agyrotropynonbackstream |
agyrotropy for thermal particles |
pop/vg_beta |
pop/beta |
plasma beta |
pop/vg_beta_parallel |
pop/betaparallel |
plasma beta component parallel to B |
pop/vg_beta_perpendicular |
pop/betaperpendicular |
plasma beta component perpendicular to B |
pop/vg_beta_anisotropy |
pop/betaperpoverpar |
ratio of perpendicular beta to parallel beta |
pop/vg_beta_anisotropy_nonthermal |
pop/betaperpoverparbackstream |
ratio of perpendicular beta to parallel beta for non-thermal particles |
pop/vg_beta_anisotropy_thermal |
pop/betaperpoverparnonbackstream |
ratio of perpendicular beta to parallel beta for thermal particles |