AP trapped particle flux maps (1966–1980)

I)

Hllit/.l

rdsl-r)m’l~ct

: N(‘~.::HII_I

I /4

NEWBL (1977) K. A. Plitxr McDonnell Douglas .4stronautics Corporalion. Code /2336s. Mail Stop I.3 3. 5301 Balsa AWU. I~unting!tw Beach. CA Y2647. IJ.S.A.

Earth’s Mann mapnclic sources : L-value.

licld

: contrihu1wns

from external

This package consists of the main subroutlnc FLDINT several supporting subroutines. FOI- a given point in space FLDlNT determines the rnagnctic field strength (main and cxtcrnal contributions). the L-value. 1he minimum field strength along the field linc, and the electron drift velocity. The IGS (75) model is used for 1he internal (core) licld and the Olson PfitTer model for the external source lields. Lvalues are obtained by 1he usual integratwn procedure along the magnetic lield line from mirror point to conjugate mire-or point. DiR‘erent from other Lcalculation programs. hohcvcl-. FLDlNT can modify the mirror points to more accurately I-cpresent drift shells of isotropic particle distribulion in the drift shell splitting region. The program also Ilags open licld lines inside the aurora1 oval. This is an excellently documented sofiwarc package that IS easy to adjust to special applications. and

On one tape (NSSDC

ID

Thi\ wf1wrc packsg!c conlalns the Intcrna1lon,~I (rcoma!mC‘lic Rcfwcncc Field (IGRF) from I945 to IYXi (\ce .‘I<;RF 1’935 IOX5 Model C‘oellicienth”. p. 561). the tieId c;~IcuI;~t~on\uhrout~nc 1:FI_DG. and the /.-shell calcul;+tion \uhroutinc SHELLG (xc “I-FLDC;S~IELLG’INTEL.G”. p 565) The IGRF modclh represent the Earth’s main iield without c\tcrnal wurcc\. The) ust’ ;I rphct-ical harmonlch cxpanaion of the scalar potential in gcoccntr~c coordinales. The NSSDC program BlLCAL products txblcs of get)magnel~c licld sti-cngth and \cclor. declination. inclination. dipole m
#PC-USA).

Klugc. (;

TRAJLST

( I Y72)

U~I-ccl computa1ion

01’ the magncl~c \hcll

(1985)

KequestCoordlna1ion NASA’GSFC, Code 933. Grcenhclt. NSI-DECncl : N(‘F::REQIJEST

MD

20771. U.S.A.

AE/AP Trapped Particle Flux Maps (1966-1980) Field-lint

.I. I.

trncin~.

Vetlc NASA <;SI‘C’. (‘ode Y-3.3,(;I-ccnbell.

This program is used by the National Space Sc~cncc Dana Ccntcr‘s Satellite Situation Center (SSC) for magnetic tieldlint trnclng. Tho main geomagnetic lield is rcprcscnted by :I sphervxl harmonics model (IGRF 65 or 75) and the crternal field by the Mead Fairfield model. Required input information includes time, year, altitude where trace should stop. latitude, longitude. and altitude where tract should start (e.g. satellite locaiion). TRAJLST is adopted to the special needs of the SSC. The source code is. unfortunately. poorly documcntcd. which may hinder use of the program for olhcr applications.

On tape (NSSDC

ID

# PGl8B).

MI)

1077 I. IJ.S.A

1’0, (,,,,<‘,(‘1

These maps conlain omnlclircctional. integral clcctron (A I’ maps) and proton (AP maps) lluxes in the cncrgy range 0.04 7 McV for electrons and 0. I 400 McV for proton% in the Earth’s radiation hclt (1. -1 I .2 to I I for clrctrons. 1. = I .I7 to 7 for proton\). The fluxc\ are stored as functions ofenergy. L-value, and B;B,, (magnetic field strength normalircd la its cqualorial [minimum] value on the lield-line). The maps arc lx~sed on data from more lhan 20 satellites from the earl> IY6Os to the mid-1970s. AE-X and AP-8 arc the latest editions in a wrlcs of updates starting with AE-I and AP-I tn lY6h

Solar-terrestrial

models and application

The progress in modeling the trapped particle population is documented in several reports as indicated in the tables below. Included in these reports are (I) a description of model map development, (2) tables and graphs of fluxes, and (3) results from flux integrating along selected (mostly circular) orbits. The different electron models AE can be distinguished as inner (L = 1.2 3) or outer (L = 3 I I) zone models and as models for solar cycle maximum or minimum conditions. AE-8 is the first model that covers the whole L range and both solar cycle extrema. The AP maps differ in energy range and solar cycle phase. AP-8 is the first model for the whole energy range and both solar cycle extrema. None of the flux maps consider time variations beyond the solar cycle minimum/maximum distinction. In the AE-5 report for inner zone electrons, the three dominant time effects were investigated : (1) magnetic storms strongly affect electrons with energies higher than 0.7 MeV at higher Lshells; (2) the Starfish nuclear explosion of July 9, 1962, increased electrons on low L-shells with intermediate energy (about I MeV); (3) the solar cycle effect is most significant for electrons with energies below 0.7 MeV. Magnetic storm effects are not yet included in any of the AE maps. For AE-5 1975 Projected and AE-6, the Starfish residue was subtracted. AE-8 is a synthesis of AE-5 Projected, AE6. AE-4. and new data from the OV3 3, OVl 19. Axr, and ATS 6 satellites. In the outer zone, because of large temporal variations, averages were taken over long intervals (six months or more). The AE-3, AE-4, and AE-8 reports also include local time functions down to L = 3 : however, these were not AE/AP

Name

Energy range (MeV)

L range

AE-I AE-2 AE-3 AE-4 AE-5 1975 Proj. AE-6 AE-8

0.3&7 0.047 0.01 6 0.044.85 0.044 0.044 0.044 0.04~7

I.2 I .2-6.3 6.6 331 I I .2-2.x I .2-2.8 I .2-2.8 1.2~11

*Only on microfiche. t Tape includes outer zone solar minimum

AE/AP

Name

Energy range (MeV)

L range

AP-I AP-2 AP-3 AP-4 AP-5 AP-6 AP-7 AP-8

3OG50 I5_~30 >50 4415 0.1-4 4m30 r50 0.1400

122.9 1.2 3.1 I .222.9 I .24.2 I .2 -6.6 1.24 1.15-m3 1.17-7

*A compressed

561

software

included in the computer code. AE-3, the model for the region of geostationary (geosynchronous) satellites. provides also tools for radiation exposure assessment. AE-I, AE-2, and AE-5 include both omni- and unidirectional flux maps. The largest errors occur where steep gradients in spatial and spectral distribution exist and where time variations are not well understood. A widely quoted error estimate is “a factor of 2”. An even larger error must be considered for differential fluxes (in angle or energy) created from the omnidirectional, integral flux maps. It should be noted that the Jensen~ Cain magnetic field model (see page 558) with epoch 1960.0 was used throughout the period when trapped radiation data were collected for all AE/AP models. Therefore, one has to be careful in extrapolating these models to later epochs. It is recommended that the map-specific epochs as listed in the tables below be used for all applications of the models.

Each model map is available on one tape, generated on IBM 7094, for use in conjunction with program MODEL. AE-8. AP-8 are part of the RADBELT package. The reports are available on microfiche (please order by B number) (NSSDC ID #MT-It to -18, #MT-21 to -28. #MT-2A, see Tables I and 2 below).

Hilberg, R. H., Teague, M. J. and Vette. J. I. (1974) Comparison of the Trapped Electron Models AE-4 and AE-5 with AE-2 and AE-3. NSSDC 74-13, Greenbelt, Maryland.

: TABLE 1, TKAPPED ELECTICONFLUX MAPS Solar cycle condition

Epoch

Minimum Minimum

7/63 8164

Min. & max. Maximum Minimum Maximum Minimum Maximum

64 & 67 I O/67 I975 1970 I964

NSSDC ID on tape

Reference Vette (1966) Vette et ul. (I 966) Vette and Lucero (I 967) Singley and Vette (1972a, b) Teague and Vctte (1972a. b) Teague and Vette (1974) Teague ef ul. (1976) Vette (1989) Vette ( 1989)

MT-2lB MT-22B MT-23A* MT-24B MT-25B MT-26Dt MT-28B MT-2AA MT-2AB

map AE-4

: TABLE 2. TRAPPED PROTONFLUX MAPS solar cycle condition

Epoch

Minimum Minimum Minimum Minimum

9/63 9163 963 9163

Maximum Minimum Maximum

I /69

version of the AP-8 maps is available

1964 1970

for solar minimum

Reference Vette (1966) Vette (1966) Vette (1966) Vette (1966) King (1967) Lavine and Vette Lavine and Vette Sawyer and Vette Sawyer and Vette

(I 969)

( 1970) (1976) (1976)

(MT-18F) and maximum

NSSDC ID on tape MT-IlB MT-12B MT-13B MT-14B MT-ISB MT-16B MT-I7B MT-lSB* MT-lSC* (MT-II(H)