European Space Agency¶
Royal Belgian Institute for Aeronomy¶
Ex. #8. effect of the magnetic field model parameters on the (B, L) coordinates¶
Description¶
The effect of the magnetic field model parameters on the (B, L) coordinates is illustrated with the help of the Olson and Pfitzer dynamical external field model (combined with a DGRF/IGRF geomagnetic model) for a given geographic location. The model parameters (Dst, solar wind velocity and density) are initialized by values downloaded from Omniweb at NSSDC for the period from 10 to 11 March 1998 () and stored in an ASCII file. The geographic location is set in geocentric coordinates at:
radius = 42000 km longitude = 225 deg. latitude = 0 deg.
Note that the epoch of the geomagnetic field model is forced at 1998.
Source¶
PROGRAM example8
C
INCLUDE 'unilib.h'
C
INTEGER*4 kunit, kinit, ifail, kint, kext, nfbm, i, noprint
INTEGER*4 kprint, kfile
CHARACTER*32 lbint, lbext
CHARACTER*3 lmon, months(12)
REAL*8 year, param(10), alpha
REAL*8 fbm, flm, fkm, fsm, fbeq, fs
TYPE(ZDAT) mdate
TYPE(ZGEO) mpos
C
C initialisation
C
DATA kunit, kinit, kint, kext, nfbm, noprint/ 6, 1, 0, 6, 1, -1/
DATA kfile, param, alpha/ 1, 10*-999.0d0, 90.0d0/
DATA months/ 'Jan','Feb','Mar','Apr','May','Jun','Jul','Aug',
: 'Sep','Oct','Nov','Dec'/
C
OPEN( unit=kfile,file='try08.txt',status='old',form='formatted')
READ(kfile,*)
READ(kfile,*)
year = 1998.0D0
C
kprint = kunit
CALL UT990 (kprint, kinit, ifail)
IF( ifail .LT. 0 )STOP
C
mpos%radius =42000.0d0
mpos%colat = 90.0d0
mpos%elong = 225.0d0
mdate%imonth = 1
mdate%secs = 0.0d0
C
C Loop
C
100 CONTINUE
C
C reading input data
C
READ(kfile,1000,end=500) mdate%iday, lmon, mdate%iyear,
: mdate%ihour, mdate%imin, param(4), param(5), param(2)
do i = 1, 12
if( lmon .eq. months(i) ) mdate%imonth = i
enddo
C
CALL UT540 (mdate)
C
C setting the magnetic field model
C
CALL UM510 (kint, year, lbint, kprint, ifail)
IF( ifail .LT. 0 )STOP
C
CALL UM520 (kext, mdate%amjd, param,
: lbext, kprint, ifail)
IF( ifail .LT. 0 )STOP
C
C evaluating the (B, L) coordinates
C
CALL UL220 (mpos, alpha, nfbm, fbm, flm, fkm, fsm, fbeq,
: fs, ifail)
C
C writing the result
C
if( kprint.gt.0 ) WRITE(kprint,1020)
WRITE(kunit,1010) mdate%amjd, param(4), param(5), param(2),
: fbm, flm, ifail
C
kprint = noprint
GOTO 100
500 CONTINUE
WRITE(kunit,*)
C
1000 FORMAT(i2,1x,a3,1x,i4,1x,i2,1x,i2,1x,f5.1,1x,f5.0,1x,f5.0)
1010 FORMAT(f12.5,f6.1,2f6.0,f8.5,f7.3,i7)
1020 FORMAT(/'Mod.Jul.day | SWD | SWV | Dst | B | Lm | ifail')
END
Results¶
UNILIB Library
Version 2.02
Developed by BIRA/IASB for ESA
0500-020000-0500
--- Main control parameters ---
UC160 (general constants):
Geoid major axis = 6378.16 km
Geoid minor axis = 6356.77 km
Mean Earth radius (Re) = 6371.20 km
Ecliptic inclination = 23.441512 deg
McIlwain Earth dipole = 0.311653 G/Re^3
UC190 (field line tracing):
Maximum step size = 477.8 km at one Re
Maximum "last" step size = 15.0 km
Minimum step size = 2.0 km
Altitude precision = 200. m
Magnetic field precision = 0.0006 %
UC192 (magnetic field evaluation):
Max. geomagnetic latitude = 85.0 deg
Minimum radius = 0.157 Re
(drift shell tracing):
Precision on L = 0.10000 %
Precision on the longitude = 0.05 deg
--- Geomagnetic field model ---
Model ( 0): IGRF 1995 Epoch 1995.
Order + 1 = 11
Calculation epoch = 1998.0 year
Colatitude of the dipole pole = 10.60 deg
Longitude of the dipole pole = -71.61 deg
Earth dipole moment = 0.301439 G/Re^3
Correction for the SAA drift = 0.00 deg
--- External magnetic field model ---
Model (6): Olson-Pfitzer dynamic
Storm activity index Dst = -6.0 nT
Solar wind density = 19.5 1/cm^3
Solar wind velocity = 277.0 km/s
Standoff distance = 9.2 Re
Planetary activity index Kp = 0.0 (magnetopause check)
Universal Time = 0.00 hrs
Greenwich angle of equinox = 167.47 deg
GEO direction of the Sun, X = -0.9962
Y = -0.0457
Z = -0.0744
dipole tilt angle = -7.06 deg
Mod.Jul.day | SWD | SWV | Dst | B | Lm | ifail
17600.00000 19.5 277. -6. 0.00119 6.451 0
17600.04167 29.0 282. -1. 0.00117 6.483 0
17600.08333 37.9 291. 4. 0.00113 6.566 0
17600.12500 37.1 292. 9. 0.00106 6.713 0
17600.16667 39.8 305. 10. 0.00094 6.991 0
17600.20833 41.4 311. 9. 0.00079 7.428 0
17600.25000 34.7 317. 1. 0.00068 7.822 0
17600.29167 24.3 325. -13. 0.00065 7.988 0
17600.33333 23.1 342. -23. 0.00064 8.034 0
17600.37500 41.6 369. -8. 0.00061 8.144 0
17600.41667 44.3 376. 5. 0.00061 8.144 0
17600.45833 28.6 384. -14. 0.00057 8.329 0
17600.50000 28.0 386. -18. 0.00057 8.339 0
17600.54167 13.7 444. -22. 0.00072 7.702 0
17600.58333 16.8 437. -26. 0.00082 7.357 0
17600.62500 14.7 486. -37. 0.00089 7.134 0
17600.66667 12.4 515. -72. 0.00083 7.314 0
17600.70833 10.6 512. -114. 0.00072 7.706 0
17600.75000 11.7 486. -112. 0.00085 7.248 0
17600.79167 11.0 534. -118. 0.00101 6.827 0
17600.83333 10.3 521. -121. 0.00105 6.731 0
17600.87500 9.3 525. -126. 0.00102 6.786 0
17600.91667 7.2 509. -123. 0.00097 6.919 0
17600.95833 7.2 491. -119. 0.00093 7.005 0
17601.00000 8.1 532. -112. 0.00089 7.123 0
17601.04167 6.1 534. -105. 0.00075 7.586 0
17601.08333 6.6 516. -97. 0.00072 7.685 0
17601.12500 6.2 534. -92. 0.00076 7.543 0
17601.16667 8.1 542. -90. 0.00075 7.597 0
17601.20833 6.2 518. -95. 0.00064 8.014 0
17601.25000 5.4 501. -88. 0.00054 8.517 0
17601.29167 7.6 517. -78. 0.00049 8.846 0
17601.33333 6.4 527. -83. 0.00054 8.541 0
17601.37500 5.0 529. -77. 0.00062 8.124 0
17601.41667 5.3 523. -75. 0.00059 8.258 0
17601.45833 5.1 515. -72. 0.00055 8.481 0
17601.50000 5.4 523. -70. 0.00056 8.445 0
17601.54167 5.3 536. -68. 0.00066 7.943 0
17601.58333 5.4 542. -71. 0.00077 7.506 0
17601.62500 5.2 540. -72. 0.00082 7.346 0
17601.66667 5.4 521. -68. 0.00082 7.359 0
17601.70833 5.4 515. -66. 0.00084 7.284 0
17601.75000 5.4 511. -66. 0.00093 7.034 0
17601.79167 5.2 517. -61. 0.00104 6.752 0
17601.83333 5.2 528. -61. 0.00109 6.633 0
17601.87500 5.1 532. -62. 0.00110 6.625 0
17601.91667 5.2 545. -70. 0.00108 6.653 0
17601.95833 4.9 517. -64. 0.00105 6.728 0
UNILIB/tags/v3.02
