README FILE for the NSSDC data set
78-079A-01N: "24/168-S SW(8.78-2.80),GZ(9/85)"
This readme describes only the 24-second proton data
("sw_protons_24s_ascii" in the nssdcftp site) and the 168-second
solar wind electron data ("sw_el_temp_168s_ascii"), leaving the
comet G-Z encounter data for another entry. As referred to in the
cover letter below, these data files were on "Tape 2" and
on files 1, 2, and 6 of "Tape 3".
The information below consists of a cover letter describing the data
when it was shipped to NSSDC, and additional notes written at NSSDC.
=====================================================================
COVER LETTER:
-------------
[Los Alamos letterhead]
Los Alamos Date: 30 September 1988
Los Alamos National Laboratory In reply refer to: ESS-8-88:49-815
Los Alamos, New Mexico 87545 Mail Stop: D438
Telephone: (505)667-5389
Dr. J. H. King
NSSDC
Code 633
NASA/Goddard Space Flight Center
Greenbelt, MD 20771
Dear Joe:
Under separate cover I am sending you 3 magnetic tapes containing high
temporal resolution plasma moments derived from data obtained by the Los
Alamos experiments on ISEE-3/ICE.
[Note added at NSSDC: It has been found that, for the proton files
at least, data values in the field labelled "maximum temperature" are
not consistently greater than the values in the field labelled "minimum
temperature." The data provider (JG) has been alerted to this. NSSDC's
belief is that somehow, for many records, the two values were written
into the wrong words of the records during LANL's preparation of this
data set years ago. In its use of these data, NSSDC tests values and
uses the larger (smaller) of values in the Tmax and Tmin fields as Tmax
(Tmin). JHK, 4/6/02]
Tape 1 contains 9 files of electron moments for the interval from 17
October 1982 through 26 December 1983 when ISEE-3 was in the distant (and
near) geomagnetic tail. Each data record contains the date, the time in
secs, the time in UT, the electron density, the electron flow speed, the
flow azimuth, the maximum electron temperatue, and the minimum electron
temperature. The format is (1X,I6,1X,2(F8.1,1X), 5(1PE11.4, 1X)).
Tape 2 contains 6 files of solar wind proton moments for the interval from
16 August 1978 through 7 October 1979 at a nominal temporal resolution of
24 sec. Each data record contains the date, the time in secs, the time in
UT, the proton density, the bulk flow speed, the bulk flow azimuth, the
maximum proton temperature, and the minimum proton temperature. The format
is identical to that of Tape 1.
Tape 3 contains 6 files. The first 2 of these files have solar wind proton
moments for the interval from 7 October 1979 through 26 February 1980,
after which time the ion instrument failed to return usable data. The
format for the data records in these 2 files and the plasma elements
included are indentical to those of Tape 2. Files 3-5 contain our electron
measurements for the 3 day interval surrounding the comet encounter in
September 1985, that is 10, 11, 12 September. Each data record in these
files contains the date, the time in secs, the time in UT, the core
density, the maximum halo temperature, the minimum halo temperature,
the total electron density, the bulk flow speed, the bulk flow azimuth, the
maximum total temperature, the minimum total temperature, the electron
heat flux and the electron heat flux azimuth. The format is (1X, I6, 1X,
2(F8.1, 1X), 5(1PE11.4, 1X), 2(/, 6(PE11.4, 1X))). Since the core and halo
parameters are derived from model fits and the other quantities are derived
from a straight numerical integration over the entire electron distribution,
the total density does not necessarily equal the sum of the core and
halo densities.
The last (6th) file on tape 3 contains solar wind electron temperature
values (the densities and flow velocities are redundant with the proton
values) for the interval from 16 August 1978 through 26 February 1980. You
will note that these dates overlap with the dates for the proton moments on
tapes 2 and 3. The format for the 6th file on Tape 3 is (1X, I6, 1X,
2(F8.1,1x), 5(1Pe11.4, 1X).
Please give me a call (505-667-5389) or send me a SPAN message
(ESSDP1::073500) if you have any questions pertaining to this submission.
Sincerely,
J. T. Gosling
JTG:mm
Cy: K. Ogilvie, GSFC/Code 602
T. VonRosenvinge, GSFC/Code 661
R. Wales, GSFC/Code 692
S.J. Bame, ESS-8/D438
CRM-4(2)/A150
========================================================================
========================================================================
ADDITIONAL NOTES:
-----------------
Additional notes on
NSSDC data sets 78-079A-01M and -01N
These data have been supplied by Dr. J. t. Gposling, Los Alamos
National Laboratory, (505)-667-5389, ESSDP1::073500 (SPAN),
and contain high temporal resolution proton and/or electron moments
derived from measurements obtained by the Los Alamos experiment on
the ISEE-3/ICE spacecraft. The ion instrument on ISEE-3 failed
on 1980-Feb-26 so no proton data are available from this instrument
after that date.
See cover letter from Dr. Gosling for details of parameters,
files and data formats. Additional information is given below.
Much of it is based on information provided by Dr. Gosling.
78-079A-01M: "84-SECOND ELECTRON MOM GEOTAIL" ("Tape 1")
1982-Oct017 to 1983-Dec-26
78-079A-01N: "24/168-S SW(8.78-2.80),GZ(9/85)" ("Tapes 2 & 3")
TAPE FORMAT
-----------
The tapes are labeled (LABEL='TAPE' for all three tapes), written
in ASCII at 6250 bpi, using a default block size of 2048.
TIME RESOLUTIONS
----------------
The time resolution for the G-Z encounter data is 24 seconds. The
time resolutions for the other files are different. It is nominally
84 seconds for the distant tail data (tape 1, all files), but
occasionally is 24 seconds. It is nominally 24 seconds for the
solar wind proton moments (tape 2 - all files, and tape 3 - first two
files). It is nominally 168 seconds for the solar wind electron
moments (tape 3, 6th file).
UNITS, ETC.
-----------
Date - is in YYMMDD format.
Time in seconds - is from start of day in SSSSS.S format (0-86400).
Time in UT - is UT time of day in HHMMSS.0 format (0.0 -235959.0).
Densities are in cm-3.
Flow speed are in km/s.
Flow azimuths are in degrees.
Temperatures are in Kelvins.
Heat fluxes are in (erg cm-2 sec-1).
Heat flux azimuths are in degrees.
COORDINATE SYSTEMS, ETC.
------------------------
The plasma bulk flow speed is measured relative to the spacecraft
and the bulk flow azimuth is measured positive from the
(spacecraft-centered) solar ecliptic (SE) -X direction toward the
SE -Y direction, i.e., 0 degrees corresponds to antisunward flow
and positive flow angles correspond to flow towards dawn (+90
deg), and negative flow angles correspond to flow towards dusk
(-90 deg). Thus,
antisunward = 0 deg = -GSEX {**on copy, G seems crossed out**}
toward dawn = +90 deg = -GSEY
sunward flow= 180 deg = +GSEX
toward dusk = -90 deg = +GSEY
Z-axis = spacecraft spin axis direction, North
The spacecraft spin axis was maintained within 0.5 degree of
perpendicular to the ecliptic.
Heat flux azimuth
-----------------
Plasma heat flux azimuth (where available) is similar to the
velocity azimuth, but it is measured from 0 to 3260 degress, i.e.,
0 and 360 degrees corresond to heat flux directed antisunward,
180 degrees corresponds to sunward heat flux, 90 degrees
corresponds to a heat flux directed toward dawn, and 270 degrees
corresponds to a heat flux directed toward dusk. Thus,
antisunward = 0, 360 deg = -GSEX {**G seems crossed out**)
toward dawn = 90 deg = -GSEY
sunward flux= 180 deg = +GSEX
toward dusk = 279 deg = +GSEY
MINIMUM AND MAXIMUM TEMPERATURES
--------------------------------
When the data are analyzed, a 2-D temperature matrix is
calculated, which is subsequently diagonalized. Then nominally,
the maximum temperature corresponds to the parallel temperature
and the minimum temperature corresponds to the perpendicular
temperature. This is done independently of the magnetic field
measurements, but there is usually good agreement between the
angle of maximum temperature and the magnetic field direction.
The alignment of the maximum temperature angle with the magnetic
field is usually within 25 degrees. However, the electron temperature
maximum is aligned perpendicular to the field about 2% of the time
in the solar wind. See papers by J. L. Philips et al. in JGR 1989,
1990.
OTHER REFERENCES
----------------
Feldman et al., JGR, v.80, 4181, 1975.
Zwickl et al., GRL, v.13, 401, 1986.
For a description of the Los Alamos instrument on the ISEE-3/ICE
spacecraft, see: Bame, S.J., J.R. Asbridge, H.E. Felthauser, J.P.
Glore, H.L. Hawk, and J. Chavez, ISEE-C solar wind plasma
experment, IEEE Trans. Geosci. Electron., GE-16, 160-162, 1978.
EPHEMERIS DATA
--------------
These data sets do not contain any spacecraft position
information. Daily values of ISEE-3/ICE position in GSE
coordinates are included in the magnetic field data from JPL and
are available as NSSDC data set 78-079A-02D.