Data Set Overview : Instrument P.I. : John D. Richardson Data Supplier : John D. Richardson Data sampling rate : 96 seconds Data Set Start Time : 1981-08-19T00:00:09.229Z Data Set Stop Time : 1981-09-04T02:51:21.885Z This Voyagers 2 data set contains two solar wind plasma data, one spanning from August 19 to September 4 , 1981, and near encounter specific data covering August 24-25. Moment parameters are given in the broader data while the near encounter data is more detailed. The fit parameters assume a convected isotropic proton Maxwellian distribution. Use of fit parameters is recommended as these are normally more accurate. Since only the first 72 or last 72 energy/charge channels are telemetered to Earth from each M-mode spectra, derived parameters change significantly only every other set of spectra so the effective time resolution is 96 second. Parameters : Data Set Parameter 'ION DENSITY' -------------------------------- Data Set Parameter Name : ION DENSITY Data Set Parameter Unit : CM**-3 Sampling Parameter Name : TIME Sampling Parameter Unit : SECOND Minimum Sampling Parameter : UNK Maximum Sampling Parameter : UNK Sampling Parameter Interval : UNK Minimum Available Sampling Int : UNK Noise Level : UNK A derived parameter equaling the number of ions per unit volume over a specified range of ion energy, energy/charge, or energy/nucleon. Discrimination with regard to mass and or charge state is necessary to obtain this quantity, however, mass and charge state are often assumed due to instrument limitations. Many different forms of ion density are derived. Some are distinguished by their composition (N+, proton, ion, etc.) or their method of derivation (Maxwellian fit, method of moments). In some cases, more than one type of density will be provided in a single data set. In general, if more than one ion species is analyzed, either by moment or fit, a total density will be provided which is the sum of the ion densities. If a plasma component does not have a Maxwellian distribution the actual distribution can be represented as the sum of several Maxwellians, in which case the density of each Maxwellian is given. Data Set Parameter 'ION TEMPERATURE' ------------------------------------ Data Set Parameter Name : ION TEMPERATURE Data Set Parameter Unit : EV Sampling Parameter Name : TIME Sampling Parameter Unit : SECOND Minimum Sampling Parameter : UNK Maximum Sampling Parameter : UNK Sampling Parameter Interval : UNK Minimum Available Sampling Int : UNK Noise Level : UNK A derived parameter giving an indication of the mean energy/ion, assuming the shape of the ion energy spectrum to be Maxwellian. Given that the ion energy spectrum is not exactly Maxwellian, the ion temperature can be defined integrally (whereby the mean energy obtained by integrating under the actual ion energy spectrum is set equal to the integral under a Maxwellian, where the temperature is a free parameter for which to solve), or differentially (whereby the slopes of the actually ion energy spectrum at various energies are matched to the slopes of a corresponding Maxwellian). The temperature parameter is often qualified with a range of applicable energies. Temperatures can be angularly anisotropic. If the ions do not have a Maxwellian distribution the actual distribution can be represented as the sum of several Maxwellians, each with a separate temperature. Data Set Parameter 'ION THERMAL SPEED' -------------------------------------- Data Set Parameter Name : ION THERMAL SPEED Data Set Parameter Unit : KM/S Sampling Parameter Name : TIME Sampling Parameter Unit : SECOND Minimum Sampling Parameter : UNK Maximum Sampling Parameter : UNK Sampling Parameter Interval : UNK Minimum Available Sampling Int : UNK Noise Level : UNK A measure of the velocity associated with the temperature of the ions. It is formally defined as the Ion Thermal Speed squared equals two times K (Boltzmann's constant) times T (temperature of ion) divided by M (ion mass). Each component of a plasma has a thermal speed associated with it. Data Set Parameter 'ION VELOCITY' --------------------------------- Data Set Parameter Name : ION VELOCITY Data Set Parameter Unit : KM/S Sampling Parameter Name : TIME Sampling Parameter Unit : SECOND Minimum Sampling Parameter : UNK Maximum Sampling Parameter : UNK Sampling Parameter Interval : UNK Minimum Available Sampling Int : UNK Noise Level : UNK A derived parameter giving the average speed and direction of motion of a plasma or plasma component. The velocity can be obtained by taking the first moment of the distribution function or by simulating the observations with some known distribution function, usually a Maxwellian, to the distribution. Velocities are given in Heliographic (RTN) coordinates: R is radially away from sun, T is in plane of sun's equator and positive in the direction of solar rotation N completes right-handed system Source Instrument Parameters : Instrument Host ID : VG2 Data Set Parameter Name : ION DENSITY Instrument Parameter Name : ION RATE Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION DENSITY Instrument Parameter Name : ION CURRENT Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION VELOCITY Instrument Parameter Name : ION CURRENT Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION TEMPERATURE Instrument Parameter Name : ION RATE Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION THERMAL SPEED Instrument Parameter Name : ION RATE Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION TEMPERATURE Instrument Parameter Name : ION CURRENT Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION THERMAL SPEED Instrument Parameter Name : ION CURRENT Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION DENSITY Instrument Parameter Name : PARTICLE MULTIPLE PARAMETERS Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ION TEMPERATURE Instrument Parameter Name : PARTICLE MULTIPLE PARAMETERS Important Instrument Parameters : 1

Confidence Level Overview : Inbound solar wind values should be accurate to within a few percent for all parameters. Data Coverage : Filename Records Start Stop ---------------------------------------------------------------------- Volume ID: VG_1601 ION_WBR.TAB 8389 1981-08-19T00:00:09.229 1981-09-04T02:51:21.885 ION_WIND.TAB 662 1981-08-24T12:01:46.633 1981-08-25T06:57:12.005 Missing Data Flag : Any column containing a value of -9, -9.9999, -999.9, -999.9999, or 9.99999e+10 (depending upon column format) is a missing data value.