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STEREO-B In-situ Measurements of Particles And CME Transients (IMPACT) Magnetic Field Vectors and Ancillary Data

This data product contains Level 1 0.125-s values of solar wind magnetic field data taken by the IMPACT/Magnetometer on STEREO-B. The interface at UCB provides access to CDF-formatted files of magnetic field data in RTN coordinates. The interface at UCLA allows selection of STEREO A or STEREO B data and of vector quantities in RTN or spacecraft coordinates. It also allows selection of either of two parameter sets: [Bx, By, Bz, B ] or [RBx, RBy, RBz, B , cone and clock angles]. Further, this interface enables easy migration between plot vs. ASCII data presentation options and among the three available resolutions (1, 8, 32 Hz). The parameter level information given below is specific to the CDF version of the data at UCB.

Laurel (LREL) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Laurel, MD, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (LREL), Station Location: (GEO Latitude 39.1, Longitude 283.2), THEMIS GBO Network

STEREO-A In-Situ Measurements of Particles and CME Transients (IMPACT) Fluxgate Magnetometer (MAG) Magnetic Field Vectors, in Spacecraft (SC) Coordinates

STEREO Ahead In-situ Measurements of Particles and CME Transients, IMPACT, Magnetometer Instrument, MAG, Magnetic Field Vectors, Level 1 Data

Voyager 2 48-s Triaxial Fluxgate Magnetometer (MAG) Magnetic Field Data Near and Beyond Termination Shock in CDF Format

The main science objectives for the Voyager Interplanetary Mission, VIM, are as follows: - investigate the structure of the solar wind magnetic fields and plasma in the inner and outer heliosphere; - conduct long term study of heliospheric evolution during different phases of the 22-year solar magnetic cycle and the 11-year solar activity cycle; - study the long term solar modulation and determine the elemental and isotopic abundances of galactic cosmic ray particles in the heliosphere; - measure radial gradients, spectra, and nuclear abundances of the anomalous component of cosmic rays from acceleration at the solar wind termination shock; - investigate local particle acceleration in the interplanetary medium from solar flare shocks and corotating interaction regions; - study propagation of solar energetic particles in the heliosphere. The average magnetic field strength produced by the spacecraft at the location of the outboard magnetometer of the dual magnetometers system on Voyager 1 and Voyager 2 is about 0.1-0.2 nT, comparable to the most probable magnetic field strength in the inner heliosheath and significantly larger than the most probable magnetic field strength in the distant supersonic solar wind. The spacecraft magnetic field is a complex, time-dependent signal that must be removed from the measured magnetic field signal in order to derive the ambient magnetic fields of the solar wind and heliosheath. Corrections must also be made for spurious magnetic signals and noise associated with the telemetry system, ground tracking systems, and other factors. Extracting the signal describing the solar wind and heliosheath from the many sources of uncertainty is a complex and partly subjective process that requires understanding of the instrument and judgement based on experience in dealing with the ever-changing extraneous signals. We estimate that for the Voyager magnetic field data the 1-sigma the uncertainty of the 48-s averages for each of the components of the magnetic field BR, BT, and BN is typically +/- 0.02 nT; the uncertainty in magnitude F1 is typically +/- 0.03 nT. F1, BR, BT, and BN can differ from one another and they may vary with time, but there is no practical way to determine these uncertainties more precisely at present. References: D.B. Berdichevsky, Voyager Mission, Detailed processing of weak magnetic fields; I - Constraints to the uncertainties of the calibrated magnetic field signal in the Voyager missions, 2009; https://vgrmag.gsfc.nasa.gov/Berdichevsky-VOY_sensor_opu090518.pdf 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., Spacecraft studies of the interplanetary magnetic field, 76, 3564, 1971.

Snap Lake (SNAP) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Snap Lake, NT, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (SNAP), Station Location: (GEO Latitude 63.6, Longitude 249.1), THEMIS GBO/UCLA Network

Trapper Creek (TRAP) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Trapper Creek, AK, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (TRAP), Station Location: (GEO Latitude 62.3, Longitude 209.8), University of Alaska Network

Dombas (DOB) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Dombas, Norway, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (DOB), Station Location: (GEO Latitude 62.1, Longitude 9.1), TGO Network

Maniitsoq (SKT) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Maniitsoq, Greenland, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (SKT), Station Location: (GEO Latitude 65.4, Longitude 307.1), DTU Network

Soroya (SOR) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Soroya, Norway, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (SOR), Station Location: (GEO Latitude 70.5, Longitude 22.2), TGO Network

Voyager 1 1.92-s Averaged Triaxial Fluxgate Magnetometer (MAG) Interplanetary Magnetic Field 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 in heliographic (RTN) coordinates, and the magnetic field strength, F2, computed from 1-hr 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 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 Sci. Rev., 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). 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 radius 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 used 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. The magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (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 as well. 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 Sci. Rev., 39, 255-316, 1984.

Gjoa Haven (GJOA/GJO) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Gjoa Haven, NU, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (GJOA/GJO), Station Location: (GEO Latitude 68.6, Longitude 264.1), MACCS Network

Van Allen Probe B Electric Field and Waves Suite (EFW) Burst Mode 1 (512 Samples/sec) Electric and Magnetic Fields, Waveform, in Spacecraft Spin (UVW) Coordinates, Level 1 (L1), 1.95 ms Data

The EFW Burst Modes provide targeted Measurements over Brief Time Intervals of 3-D Electric Fields, 3-D Wave Magnetic Fields, and Spacecraft Potential. There are two EFW Burst Modes: BURST1 (B1), Medium-Rate 512 samples/s nominal and BURST2 (B2), Higher-Rate, 16384 samples/s nominal. The Burst 1 Mode Data includes three components of the Electric Field (E12_B1, E34_B1, E56_B1), six Components of the Spacecraft-Sensor Potential (V1_B1 through V6_B1), and three Components of the AC Magnetic Field (SCM_U_B1, SCM_V_B1, SCM_W_B1 from the EMFISIS Search Coil Magnetometer). The Burst 2 Mode Data returns a similar Complement of Electric Field (E_12ac_B2, E34ac_B2, E56ac_B2), Search Coil (SCM_B2, SCM_2B2, and SCM_B2 again from the EMFISIS Search Coil Magnetometer) and Single-ended Potential Measurements (V1ac_B1 through V6ac_B2) with the exception that in the Default Mode the Single-ended Potential and Electric Field Signals are AC coupled with a higher Gain. All Quantities are in "uvw" Coordinates where "u" and "v" are the Sensor Coordinates rotating with the Spacecraft and "w" points along the Spacecraft Spin Axis. Burst Waveform CDF Files are available. The three Data Types available are the Electric Field "E" the Searchcoil Magnetic Field "MSC" and Antenna Potential "V". The Suffix on each of these is either "B1" or "B2". B1 or Burst 1 is the Human-in-the-Loop Burst Type, meaning that both Collection and Playback (for arbitrary Lengths of Time) are requested on the Ground. B2 or Burst 2 is automatically telemetered as short Bursts based on an onboard Triggering Algorithm, typically set to trigger on large Amplitude Signals near 1 kHz. Sample Rates for B1 and B2 can and are changed depending on varying Science Goals.

NASA Stennis Space Center (BSL) Ground-based Vector Magnetic Field (L2) 1.0 s Data

NASA Stennis Space Center, MS, Ground-based Vector Magnetic Field Level 2 Data, 1.0 s Time Resolution, Station Code: (BSL), Station Location: (GEO Latitude 30.4, Longitude 270.4), USGS Network

Andenes (AND) Ground-based Vector Magnetic Field (L2) 1.0 min Data

Andenes, Norway, Ground-based Vector Magnetic Field Level 2 Data, 1.0 min Time Resolution, Station Code: (AND), Station Location: (GEO Latitude 69.3, Longitude 16.0), TGO Network

Colville National Forest (NEW) Ground-based Vector Magnetic Field (L2) 1.0 s Data

Colville National Forest, WA, Ground-based Vector Magnetic Field Level 2 Data, 1.0 s Time Resolution, Station Code: (NEW), Station Location: (GEO Latitude 48.3, Longitude 242.9), USGS Network

Barrow (BRW) Ground-based Vector Magnetic Field (L2) 1.0 s Data

Barrow, AK, Ground-based Vector Magnetic Field Level 2 Data, 1.0 s Time Resolution, Station Code: (BRW), Station Location: (GEO Latitude 71.3, Longitude 203.4), USGS Network

Park Site (PKS) Ground-based Vector Magnetic Field (L2) 1.0 s Data

Park Site, SK, Ground-based Vector Magnetic Field Level 2 Data, 1.0 s Time Resolution, Station Code: (PKS), Station Location: (GEO Latitude 52.5, Longitude 252.8), STEP Polar Network

MMS 2 Digital Signal Processor (DSP) Search Coil Magnetometer (SCM), Magnetic Field Power Spectral Density, Level 2 (L2), Fast Mode, 2 s Data

The MMS magnetic field power spectral density (BPSD) is computed onboard by the Digital Signal Processor (DSP). The fast Fourier transform (FFT) calculation is performed on a digitized version of analog signals from the Search Coil Magnetometer (SCM) in the SCM123 coordinate system, see SCM data product guide for details, https://lasp.colorado.edu/mms/sdc/public/datasets/fields/. This data product is computed in space from individual components that are not synchronized to the 1 second pulse. Therefore, the timing between channels can be inaccurate by a fraction of a second. The samples times are interval start times taken from the x component. The spectra are calculated via a 1024-point FFT algorithm on piecewise continuous sets of waveform data. Nine signals can be processed simultaneously. Six of the twelve DC-coupled E, DC-coupled V, or SCM signals (16384 samples/s) are selected for spectral processing at 100% duty cycle. In addition, the three AC-coupled signals (262,144 kS/s) each can be processed at 6.25% duty cycle. Each of the nine signals has 16, 1024-point FFT operations every second; the field-programmable gate array (FPGA) performs 144 FFTs per second. The FFT is performed by an arithmetic logic unit (ALU), which is controlled by a state machine. Both are hard-coded into the FPGA. The operation starts by applying a 1024-point Hanning window onto a waveform. Next, an FFT is implemented. The FFT is broken into a series of "butterfly" operations performed by the ALU. The result has real and imaginary data. Power spectra are calculated by taking the sum of squares of real and imaginary values (the ALU includes a multiplier), which produces a power spectrum with 512 frequency bins. The frequency bins are then combined to give pseudo-logarithmic frequency spacing (del f)/f. The spectra are reduced to 88 frequency bins with (del f)/f between 6% and 12% when possible. Narrow-band emissions can be fit to an accuracy of (del f)/f ~3%, allowing for an accurate determination of plasma density. The spectra can be averaged in time. The fastest reporting rate of any signal is 16 spectra per second. Reporting rates can be as slow a one spectra every 16 s (averaging 256 spectra). The DSP and SCM instrument papers can be found at https://link.springer.com/article/10.1007/s11214-014-0115-x and https://link.springer.com/article/10.1007/s11214-014-0096-9, respectively. The DSP and SCM data product guides can be found at https://lasp.colorado.edu/mms/sdc/public/datasets/fields/.

Muono (MUO) Ground-based Vector Magnetic Field (L2) 10.0 s Data

Muono, Finland, Ground-based Vector Magnetic Field Level 2 Data, 10.0 s Time Resolution, Station Code: (MUO), Station Location: (GEO Latitude 68.0, Longitude 23.5), IMAGE Network

Coral Harbour (CHBR) Ground-based Vector Magnetic Field (L2) 0.5 s Data

Coral Harbour, NU, Ground-based Vector Magnetic Field Level 2 Data, 0.5 s Time Resolution, Station Code: (CHBR), Station Location: (GEO Latitude 64.2, Longitude 276.7), MACCS Network