Find research datasets worth reusing

THEMIS-A: On Board Fast Fourier Transform (FFT) power spectra of Electric (EFI) and Magnetic (SCM) field measurements, for particle and wave burst survey modes.

On Board Fast Fourier Transform (FFT) power spectra of Electric (EFI) and Magnetic (SCM) field measurements for particle and wave burst survey modes. Spectra are produced only in Particle Burst and Wave Burst modes; only a preselected four of the signals listed in Table 1 are input at any time. Data fed through the FFT while not in Particle or Wave Burst modes is automatically disgarded. The FFTs (Cooley-Tukey algorithm) are conducted as an integral part of the power spectrum calculation by the Field Programable Gate Arrays (FPGAs). A CORDIC algorithm is used for sine/cosine calculations. The data has raw resolution of 1024 pts for 8,192 sample/sec signals and 2048 pts for 16,384 sample/sec signals (EAC measurements only). Signals at 8,192 samples/sec are handled by 1024-point FFTs, while those at 16,384 samples/sec go through 2048-point FFTs. Past and current signal configurations for specific spacecraft are listed bellow in Table 2. The spectra are arranged into log spaced frequency bins in steps of 16, 32, or 64. Cadence is adjusted to keep packet size constant (i.e. increasing the fequency resolution by a factor of 2 decreases the sampling rate by 1/2). The frequency bins cover a range of 0 Hz to 4 kHz. Table 1: FFT Input Signals. Signal Description SCMX, SCMY, SCMZ: Three axis magnetic fiend from SCM V1 through V6: Probe-spacecraft voltage for all six EFI sensors E12DC, E34DC, E56DC: DC-coupled electric field measured from opposing EFI sensors E12AC, E34AV, E56AC: AC-coupled electric field measured from opposing EFI sensors E12HF: High frequency electric field from EFI Table 2: Spacecraft specific configurations. All probes were initially set to use EDC34, EDC56, SCM2, and SCM3 signals for both particle and wave burst modes. Output was set to 16 frequency bins at 4 Hz. Configuration Changes: 9 June 2008: Particle burst spectra resolution increased from 16 to 64 bins and cadence slowed from 4 Hz to 1 Hz for closer analysis of spectral features. N/A: Particle burst spectra on all probes reconfigured to 64 bins at 1 Hz. 15 Aug 2008: E34DC and E56DC inputs switched to E34AC and E56AC to reduce impact of wake fields on FFT spectral measurements. 15 Oct 2008: Particle burst spectra resolution reduced from 64 to 32 bins and the rate increased from 1 Hz to 2 Hz; a response to noise from plasma wake fields in the 64 bin spectra. Table 3: Instrument-Spacecraft Physical Configuration Instrument Alignment in Spacecraft Geometric coordinates (SPG). See THEMIS website for coordinate system details and mechanical drawings. EFI boom 1: Along positive X-axis EFI boom 2: Along negative X-axis EFI boom 3: Along positive Y-axis EFI boom 4: Along negative Y-axis EFI boom 5: Along positive Z-axis EFI boom 6: Along negative Z-axis SCM *The SCM uses an instrument specific set of axes; an orthogonal system centered instrument with the X-axis 12.1 degrees from the SPG X-axis.

Pello (PEL) Ground-based Vector Magnetic Field (L2) 10.0 s Data

Pello, Finland, Ground-based Vector Magnetic Field Level 2 Data, 10.0 s Time Resolution, Station Code: (PEL), Station Location: (GEO Latitude 66.9, Longitude 24.1), IMAGE Network

Voyager 2 48-s Triaxial Fluxgate Magnetometer (MAG) Magnetic Field Data in CDF Format

This data set includes the Voyager spacecraft number (1 or 2), the date-time in decimal year (90.00000 is day 1 of 1990), the magnetic field strength, F1, computed from high-resolution magnitudes, the elevation and azimuth angles (degrees) in heliographic (RTN) coordinates, and the magnetic field strength, F2, computed from hour averages of the components. The vector components of B can be computed from F2 and the two angles. The elevation angle is the latitude angle above or below the solar equatorial plane, and the azimuth angle is in the direction of orbital motion around the Sun from the projection of the Sun-to-spacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, Magnetic-Field Experiment for Voyager-1 and Voyager-2, Space Science Reviews, 21 (3), 235-257, 1977. At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al. 1977) was adopted. At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radial vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. (1994) and in Appendix A of Burlaga et al. (2002). References: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, Magnetic-Field Experiment for Voyager-1 and Voyager-2, Space Science Reviews, 21 (3), 235-257, 1977. Burlaga, L.F., Merged interaction regions and large-scale magnetic field fluctuations during 1991 - Voyager-2 observations, J. Geophys. Res., 99 (A10), 19341-19350, 1994. Burlaga, L.F., N.F. Ness, Y.-M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. Ness et al., 1973. Coordinate Systems: Interplanetary magnetic field studies make use of two important coordinate systems, the Heliographic Inertial (HGI) coordinate system and the Heliographic (HG) coordinate system. The HGI coordinate system is use to define the spacecraft's position. The HGI system is defined with its origin at the Sun. There are three orthogonal axes, X(HGI), Y(HGI), and Z(HGI). The Z(HGI) axis points northward along the Sun's spin axis. The X(HGI)-Y(HGI) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(HGI) axis. The X(HGI) axis drifts slowly with time, approximately one degree per 72 years. Magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center, the HGI origin, to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(HGI)-Y(HGI) plane too. The Z(HG) axis is chosen to complete the orthonormal triad. An excellent reference guide with diagrams explaining the HGI and HG systems may be found in L. F. Burlaga, MHD Processes in the Outer Heliosphere, Space and Science Reviews, 39, 255-316. Support data calib_flag_on, calib_flag_MF, and calib_flag_offset are added to file version 2. Variable calib_flag_on consists of points where bit 4 or 5 in variable magStatus equal 1. Variable calib_flag_MF represents observations where magnetometer was in cailbration mode. Variable calib_flag_offset represent delay between data points when the magnetometer was in calibration mode and data points where magStatus variable indicated calibration periods. Due to specific shape of magnetometer data profile variable calibration_flag_

Kodiak (KODK) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Kodiak, AK, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (KODK), Station Location: (GEO Latitude 57.8, Longitude 207.6), THEMIS GBO Network

Wind Magnetic Field Investigation (MFI) Data at full resolution

This data product contains Wind MFI full resolution magnetic field magnitude and GSE and GSM Cartesian components. Time resolution is typically 0.046s or 0.092s from launch through 1997, and is 0.092s thereafter. Final Version 5 data are accessible to within about 3 months of current date, newly defined Version 4 data (with final Bz offsets and not-yet-final spacecraft position vectors) between 3 months and about 2 weeks of current date, and newly defined Version 3 data (with the most recently determined Bz offset value, not yet final for the Version 3 interval) from 2 weeks to about 2 days of current.

OMNI Combined Heliopheric Observations (COHO), Merged Magnetic Field, Plasma and Ephermeris, Definitive Hourly Data

Hourly Averaged Definitive Multispacecraft Interplanetary ParametersData. The Heliographic Inertial, HGI, Coordinates are Sun-Centered and inertially fixed with respect to an X-Axis directed along the Intersection Line of the Ecliptic and Solar Equatorial Planes. The Solar Equatorial Plane is inclined at 7.25° from the Ecliptic. This Direction was towards Ecliptic Longitude of 74.367° on 1 January 1900 at 1200 UT but because of Precession of the Celestial Equator, this Longitude increases by 1.4° per Century. The Z-Axis is directed Perpendicular and Northward from the Solar Equator, and the Y-Axis completes the Right-Handed Set. This System differs from usual Heliographic Coordinates, e.g. Carrington Longitudes, which are fixed in the Frame of the Rotating Sun. The RTN System is fixed at a Spacecraft or a Planet. The R-Axis is directed radially away from the Sun, the T-Axis is the Cross Product of the Solar Rotation Axis and the R-Axis, and the N-Axis is the Cross Product of the R-Axis and T-Axis. At 0° Heliographic Latitude when the Spacecraft is in the Solar Equatorial Plane, the N-Axis and Solar Rotation Axis are Parallel. Latitude and Longitude Angles of Solar Wind Plasma Flow are generally measured from the Radius Vector away from the Sun. In all cases, Latitude Angles are Positive for North-Going Flow. The Flow Longitude Angles have been treated differently for the Near-Earth Data, i.e. the OMNI, and for the Deep Space Data. The Flow is Positive for the Near-Earth Data when coming from the Right Side of the Sun as viewed from the Earth, i.e. flowing toward +Y from -X GSE or Opposite to the Direction of Planetary Motion. On the other hand, the Flow Longitudes for the Deep Space Spacecraft use the opposite Sign Convection, i.e. Positive for Flow in the +T Direction in the RTN System.

THEMIS-B: On Board spin fits (FIT) of Electric (EFI) and Magnetic (FGM) field. On-Board Spin-fit electric and magnetic field data

THEMIS-B: On Board spin fits of Electric (EFI) and Magnetic (FGM) fields. This file contains data EFI and FGM that has been despun on-board to 3 second resolution. It stores meta information like the number of points that contributed to each spin and the standard deviation of those points. For the EFI data it also stores variables with the Z component of the EFI data zeroed and the Z component of the EFI estimated using the E.B=0 equality. The need to use an estimated Z axis for the EFI is due to error in measurements from the EFI axial booms. These data are provided in DSL (despun spacecraft L-Z vector), GSM, and GSE coordinates.

Oulujarvi (OUJ) Ground-based Vector Magnetic Field (L2) 10.0 s Data

Oulujarvi, Finland, Ground-based Vector Magnetic Field Level 2 Data, 10.0 s Time Resolution, Station Code: (OUJ), Station Location: (GEO Latitude 64.5, Longitude 27.2), IMAGE Network

Tucson (TUC) Ground-based Vector Magnetic Field (L2) 1.0 s Data

Tucson, AZ, Ground-based Vector Magnetic Field Level 2 Data, 1.0 s Time Resolution, Station Code: (TUC), Station Location: (GEO Latitude 32.2, Longitude 249.3), USGS Network

Kuujjuaq (KUUJ) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Kuujjuaq, QC, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (KUUJ), Station Location: (GEO Latitude 58.3, Longitude 291.8), THEMIS GBO/UCLA Network

DE 1 Plasma Wave Instrument (PWI) Step Frequency Correlator Electric and Magnetic Field Spectral Density

Two Dynamics Explorer (DE) spacecraft were launched August 3, 1981, and placed into coplanar polar orbits with DE-1 in a highly elliptical orbit and DE-2 in a lower more circular orbit. The primary objective of the DE program was to investigate magnetosphere-ionosphere-atmosphere coupling processes. The DE mission provided a wealth of new information on a wide variety of magnetospheric plasma wave phenomena including auroral kilometric radiation, auroral hiss, Z mode radiation, narrow-band electromagnetic emissions associated with equatorial upper hybrid waves, whistler mode emissions, wave-particle interactions stimulated by ground VLF transmitters, equatorial ion cyclotron emissions, ion Bernstein mode emissions, and electric field turbulence along the auroral field lines. These files contain calibrated, full resolution, data from the DE-1 Plasma Wave Instrument (PWI). This instrument was designed and built by the plasma wave group at The University of Iowa, Department of Physics and Astronomy, in collaboration with investigators at Stanford University's STAR Laboratory. It measured plasma wave phenomena and quasi-static electric fields using paired combinations of five PWI sensors: a 200m tip-to-tip long wire electric antenna deployed in the spacecraft spin plane, a 9m tip-to-tip tubular electric antenna deployed along the spacecraft spin axis, a short 0.6m electric antenna, mounted on the boom and oriented parallel to the long wire antenna, a magnetic loop antenna mounted on the boom and oriented to measure the component of the magnetic field parallel to the long wire antenna, and a magnetic search coil antenna, also mounted on a boom and oriented to measure the magnetic field parallel to the spacecraft spin axis. The PWI main electronics unit consisted of a Step Frequency Correlator (SFC), a Low Frequency Correlator (LFC), a Wideband Analog Receiver (WBR) and a Linear Wave Receiver (LWR). Only the SFC data are included in these files. The LFC data were provided in a companion fileset. A dataset containing available high rate WBR LWR data may be provided in the future. The SFC consisted of two Step Frequency Receivers (SFR-A and SFR-B) which provided amplitude measurements of the electric and magnetic fields from 100 Hz to 400 kHz and in-phase and quadrature-phase correlations of signals from any selected antenna pair. Phase data are not provided in these datasets.

Brorfelde (BFE) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Brorfelde, Denmark, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (BFE), Station Location: (GEO Latitude 55.6, Longitude 11.7), DTU Network

Qaanaaq (THL) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Qaanaaq, Greenland, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (THL), Station Location: (GEO Latitude 77.5, Longitude 290.8), DTU Network

Linares (LRES) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Linares, Mexico, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (LRES), Station Location: (GEO Latitude 24.9, Longitude 260.5), McMAC Network

Nain (NAIN/NAN) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Nain, NL, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (NAIN/NAN), Station Location: (GEO Latitude 56.4, Longitude 298.3), MACCS Network

Wind Magnetic Field Investigation (MFI) Full Resolution Data in RTN Coordinates

This data product contains Wind MFI full resolution magnetic field magnitude and RTN Cartesian components. Time resolution is typically 0.046s or 0.092s from launch through 1997, and is 0.092s thereafter. Final Version 5 data are accessible to within about 3 months of current date, newly defined Version 4 data (with final Bz offsets and not-yet-final spacecraft position vectors) between 3 months and about 2 weeks of current date, and newly defined Version 3 data (with the most recently determined Bz offset value, not yet final for the Version 3 interval) from 2 weeks to about 2 days of current.

Amderma (AMD) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Amderma, Russia, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (AMD), Station Location: (GEO Latitude 69.6, Longitude 60.2), AARI Network

Pevek (PBK) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Pevek, Russia, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (PBK), Station Location: (GEO Latitude 70.1, Longitude 170.9), AARI Network

Arctic Village (ARCT) Ground-based Vector Magnetic Field (L2) 1.0 s Data

Arctic Village, AK, Ground-based Vector Magnetic Field Level 2 Data, 1.0 s Time Resolution, Station Code: (ARCT), Station Location: (GEO Latitude 68.1, Longitude 214.4), University of Alaska Network

Kenai (KENA) Ground-based Vector Magnetic Field (L2) 1.0 s Data

Kenai, AK, Ground-based Vector Magnetic Field Level 2 Data, 1.0 s Time Resolution, Station Code: (KENA), Station Location: (GEO Latitude 60.6, Longitude 208.7), THEMIS GBO/UCLA Network