Lepedea data
INTRODUCTION
This directory provides access to distribution function and moments data
taken from the University of Iowa LEPEDEA (Low Energy Proton and Electron
Differential Energy Analyzer) during many magnetotail passes of the IMP 8
spacecraft (at ~200,000 km). The data are at 3-min. resolution.
The IMP 8 LEPEDEA is described at the U. Iowa web site at
http://www-pi.physics.uiowa.edu/www/imp/
and in L.A. Frank et al., J. Geophys. Res., 81, p. 5859, 1976.
The LEPEDEA Principal Investigator was L.A. Frank. The preparation of
the data at U. Iowa for submission to NSSDC was guided by C. Huang.
A browse capability to aid in data selection is provided at
http://omniweb.sci.gsfc.nasa.gov/ftpbrowser/.
The data were originally provided to NSSDC as 22 files on 6 magnetic tapes. Each
file typically held many days of binary data. Details on coverage are given below.
Pairs of records give proton then electron data for a common time. Most of the data
were distribution function data (fluxes in each of 15 energy bins in each of 16
azimuthal sectors). Also included in each record were time words, spacecraft
location words, and density, temperature and, for protons only, flow velocity
X and Y components.
The general time period covered is January, 1978, through December, 1980,
then October, 1982, through December, 1983, and finally April through June
of 1986. These intervals correspond to (1) good overlap with the ISEE
mission, (2) the ISEE-3 deep-tail period, and (3) the PROMIS interval.
A detailed listing of which days are included in each file is given below.
There are two classes of data files available in this directory. The first
class of data files correspond in content and time span to the 22 original
files, although they have been converted to ASCII and then G-zipped at
NSSDC. The second class (one non-zipped ASCII file, lep_N_V.dat) contains
only the density and speed moments data, along with time and the spacecraft
position words. The records of this moments file were constructed by taking
all the data of the full proton records except the distribution function
data, and adding in the electron density value from the companion full
electron record.
----------------------------------------------------------
FULL DATA RECORDS: FORMAT and CONTENTS
Word No. Item Description
-------- ----------------
1 1 or 2 (=1 for protons, =2 for electron)
2 Year (78,79,...86)
3 Day of the Year (1,2,...366)
4 HR, MIN, SEC AS A 6 DIGIT NUMBER, HR * 10000 + min * 100 + SEC
5 Xsm (GSM X component of IMP position vector, units = Re)
6 Ysm
7 Zsm
8 DZFM (distance in Re to the neutral sheet using the Fairfiel model)
9 Density (cm**-3)
10 Vx (km/s) for Proton data; 999 for Electron data
11 Vy (km/s) for Proton data; 999 for Electron data
12 DVx (uncertainty in Vx; 999 for Electron data)
13 DVy (uncertainty in Vy; 999 for Electron data)
14 ECM(Temperature in eV)
15-29 data for sector 1-16 at energy level 1 ***
31-46 data for sector 1-16 at energy level 2
47-62 data for sector 1-16 at energy level 3
63-78 data for sector 1-16 at energy level 4
59-94 data for sector 1-16 at energy level 5
95-110 data for sector 1-16 at energy level 6
111-126 data for sector 1-16 at energy level 7
127-142 data for sector 1-16 at energy level 8
143-158 data for sector 1-16 at energy level 9
159-174 data for sector 1-16 at energy level 10
175-190 data for sector 1-16 at energy level 11
191-206 data for sector 1-16 at energy level 12
207-222 data for sector 1-16 at energy level 13
223-238 data for sector 1-16 at energy level 14
239-254 data for sector 1-16 at energy level 15
255-270 data for sector 1-16 at energy level 16
*** The data are distribution function values f(Vx, Vy) in units of
number of particles * seconds**3 * cm**-6. Hence an integration over
velocity space gives the number density.
Format for reading unzipped records:
FORMAT(I2,I3,I4,I7.6,4F7.2,F7.3,4F7.0,1PE9.2/15(1P16E9.2,/),1P16E9.2)
(Energy level 16 should generally be ignored - note that it is not listed in
the energy range given below.)
Every Proton logical data record is followed by an Electron
logical data record with the same Time and Orbital Position data.
From word 17 to 272 invalid data may appear with value 9.9E+35.
The angles (in degrees) corresponding to the sectors are as follows:
Sector Angle range Center of sector
--------------------------------------------------------
1 338-1 349.5
2 1-23 12
3 23-46 34.5
4 46-68 57
5 68-91 79.5
6 91-113 102
7 113-136 124.5
8 136-158 147
9 158-181 169.5
10 181-203 192
11 203-226 214.5
12 226-248 237
13 248-271 259.5
14 271-293 282
15 293-316 304.5
16 316-338 327
The energies (in eV) corresponding to the levels for the protons are:
Level Energy
-------------------------------
1 5.73e+l
2 8.40e+l
3 1.24e+2
4 2.29e+2
5 3.32e+2
6 5.0e+2
7 9.89e+2
8 1.29e+3
9 2.29e+3
10 4.32e+3
11 6.63e+3
12 9.13e+3
13 1.62e+4
14 2.29e+4
15 3.77e+4
The energies (in eV) corresponding to the levels for the electrons are:
Level Energy
------------------------------
1 6.63e+l
2 9.72e+l
3 1.44e+2
4 2.65e+2
5 3.85e+2
6 5.79e+2
7 1.15e+3
8 1.49e+3
9 2.65e+3
10 4.99e+3
11 7.67e+3
12 1.06e+4
13 1.88e+4
14 2.65e+4
15 4.36e+4
------------------------------------------------------------------------------
THE lep_N_V.dat FILE: FORMAT AND CONTENTS
Word No. Item Description
-------- ----------------
1 Year (78,79,...86)
2 Day of the Year (1,2,...366)
3 HR, MIN, SEC AS A 6 DIGIT NUMBER, HR * 10000 + min * 100 + SEC
4 Xsm (GSM X component of IMP position vector, units = Re)
5 Ysm
6 Zsm
7 DZFM (distance in Re to the neutral sheet using the Fairfiel model)
8 Proton Density (cm**-3)
9 Electron Density (cm**-3)
10 Vx (km/s) for Proton data
11 Vy (km/s) for Proton data
12 DVx (uncertainty in Vx
13 DVy (uncertainty in Vy
14 ECM(Temperature in eV)
Format for reading:
FORMAT(I2,I4,I7.6,4F7.2,F7.3,F7.3,4F6.0,1PE9.2)
-----------------------------------------------------------------
NAMES OF FILES AND DAYS INCLUDED IN EACH OF THE FILE.
Name of data file DAYS INCLUDED
---------------- -------------
lep78_009_036.dat 9 10 11 12 21 22 23 24 34 35 36
lep78_047_071.dat 47 48 60 71
lep78_125_138.dat 125 126 138
lep78_138_188.dat 138 150 151 152 162 163 164 174
175 176 186 187 188
lep78_198_238.dat 198 199 200 211 213 223 225 236
237 238
lep78_250_287.dat 250 261 262 263 275 286 287
lep78_299_324.dat 299 300 323 324
lep78_336_338.dat 336 337 338
lep79_008_087.dat 8 9 10 20 21 22 32 33 34 46 86 87
lep79_098_361.dat 98 99 100 110 111 112 123 124 125
135 136 137 147 148 149 159 160 161
162 172 173 174 185 186 187 198 199
213 236 249 260 261 273 274 286 287
299 300 311 312 323 324 325 335 336
337 347 348 349 350 359 360 361
lep80_071_098.dat 71 72 84 96 97 98
lep80_109_148.dat 109 110 111 121 122 123 134 135 136
146 147 148
lep80_159_186.dat 159 160 161 171 172 173 185 186
lep80_197_223.dat 197 198 210 211 223
lep80_236_274.dat 236 249 260 261 262 273 274
lep80_274_322.dat 274 275 285 286 287 297 298 309 310
311 312 322
lep80_322_361.dat 322 323 335 348 349 360 361
lep82_297_361.dat 297 298 310 311 322 323 335 347 361
lep83_009_273.dat 9 21 22 33 34 35 59 71 72 83 84 95
96 108 109 120 121 122 148 158 159
160 172 173 174 185 186 195 197 210
211 221 223 236 246 247 248 249 259
260 261 272 273
lep83_285_351.dat 285 297 298 300 323 324 325 337 350 351
lep86_096_123.dat 96 97 98 108 110 121 122 123
lep86_134_161.dat 134 135 136 146 147 148 159 160 161
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Note that an FTPBrowser interface to this dataset, providing data
subsetting and and graphical browsing, is available at
"http://omniweb.sci.gsfc.nasa.gov/ftpbrowser/"
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Related data and directories:
SPDF Data and Orbits Services
--------------
SPDF Contact: Natalia Papitashvili ,
Please acknowledge NASA's Space Physics Data Facility for data usage.
Authorizing NASA Official: Dr. R.E. McGuire, Head, SPDF, NASA Goddard Space Flight Center
301-286-7794, e-mail: Robert.E.McGuire@nasa.gov
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