Abstract
On board the SOHO spacecraft poised at L1 Lagrange point, the SWAN instrument is mainly devoted to the measurement of large scale structures of the solar wind, and in particular the distribution with heliographic latitude of the solar wind mass flux. This is obtained from an intensity map of the sky Lymanα emission, which reflects the shape of the ionization cavity carved in the flow of interstellar H atoms by the solar wind. The methodology, inversion procedure and related complications are described. The subject of latitude variation of the solar wind is shortly reviewed: earlier Lymanα results from Prognoz in 1976 are confirmed by Ulysses. The importance of the actual value of the solar wind mass flux for the equation of dynamics in a polar coronal hole is stressed. The instrument is composed of one electronic unit commanding two identical Sensor Units, each of them allowing to map a full hemisphere with a resolution of 1°, thanks to a two-mirrors periscope system. The design is described in some details, and the rationale for choice between several variants are discussed. A hydrogen absorption cell is used to measure the shape of the interplanetary Lymanα line and other Lyman α emissions. Other types of observations are also discussed : the geocorona, comets (old and new), the solar corona, and a possible signature of the heliopause. The connexion with some other SOHO instruments, in particular LASCO, UVCS, SUMER, is briefly discussed.
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Ajello J.M., Pryor W.R., Barth C.A., Hord C.W., Stewart A.I.F., Simmons K.E., Hall D.T.: 1994,Astron. Astrophys.,289, 283–303
Ajello J.M., Stewart A.I., Thomas G.E., Graps A.: 1987,Astrophys. J.,317, 964–986
Artzner, G: 1982, Thèse de doctorat d'Etat, Université de Paris 7
Baranov V.B., Malama Yu. G.: 1993,J. Geophys. Res.,98,A9, 15,157–15,163
Bertaux J.L.: 1975,J. Geophys. Res.,80, 639–642
Bertaux J.L., Blamont J.E.: 1970,C.R. A.S.,270, 1581–1584
Bertaux J.L., Blamont J.E., Mironova E.N., Kurt V.G., Bourgin M.C.: 1977,Nature,270, 156–158
Bertaux J.L., Blamont J.E., Festou M.: 1973,Astron. Astrophys.,25, 415–430
Bertaux J.L., Blamont J.E.: 1971,Astron. Astrophys.,11, 200–217
Bertaux J.L., Lallement R.: 1984,Astron. Astrophys.,140, 230–242
Bertaux J.L., Lallement R., Kurt V.G., and Mironova E.N.: 1985,Astron. Astrophys., 150, 1–20
Berthé M., Ph.D. Thesis, Université de Paris 6, January 1995
Blum P.W. and Fahr H.J.: 1970,Astron. Astrophys.,4, 280
Blum P., Gangopadhyay P., Ogawa H.S., and Judge D.L.: 1993,Astron. Astrophys.,272, 554
Bzowski M. and Rucinski D.: 1995,Space Science Rev.,72, 467–470
Cook J.W., Meier R.R., Bruekner G.D., Van Hoosier M.E.: 1981,Astron. Astrophys.,97, 394
Cummings A.C., Stone E.C., Webber W.R.: 1993,J. Geophys. Res.,98,A9, 15165–15168
Fahr H.J., Ripken H.W. and Lay G.: 1981,Astron. Astrophys.,102, 359
Fite W.L., Smith A.C.H. and Stebbings R.F.: 1962,Proc. Roy. Soc. A.,268, 527
Grec G., Fossat E., Pomerantz M.: 1980,Nature,288, 541
Gurnett D.A., Kurth W.S., Allendorf S.C., Poynter R.L.: 1993,Science,262, 199
Holzer T.E., Lallement R., Munro R.H.: 1986,J. Geophys. Res.,91, 6751–6759
Holzer T.E., Leer E.: 1980,J. Geophys. Res.,85, 4665
Huomo H., Hannula H., Viherkanto K.: 1992,Proc. Fifth European Space Mechanism and Tribology Symposium, ESA SP-334
Joselyn J.A. and Holzer T.E.: 1975,J. Geophys. Res.,80, 903
Kissel J., Sagdeev R.Z., Bertaux J.L.et al.: 1986,Nature,321, 280
Kojima M., Kakinuma T.: 1987,J. Geophys. Res.,92, A7, 7269–7279
Kumar S., Broadfoot A.L.: 1979,Astrophys. J.,228, 302–311
KyröLä E., Summanen T. and Raback P.: 1994,Astron. Astrophys.,288, 299–314
Lallement R., Bertaux J.L., Kurt V.G., Mironova E.N.: 1984,Astron. Astrophys.,140, 243
Lallement R. Bertin P.: 1993,Astron. Astrophys.,266, 479–485
Lallement R., Bertaux J.L., Dalaudier F.: 1985,Astron. Astrophys., 150, 21
Lallement R., Holzer T.E., Munro R.H.: 1986,J. Geophys. Res.,91, 6751
Lallement R., Bertaux J.L.: 1990,Astron. Astrophys.,231, L3
Lallement R., Bertaux J.L., Clarke J.T.: 1993,Science,260, 1095
Lallement R., Bertaux, J.L., Kurt V.G.: 1985,J. Geophys. Res.,90, 1413
Lallement R., Kyrölä E. and Summanen T.,Space Science Rev.,72, 455
Lallement R., Malama Yu. G., Quémerais E., Bertaux J.L., Zaitsev, N.A.: 1992,Astrophys. J.,396, 696
Lallement R., Stewart I.A.: 1990,Astron. Astrophys.,227, 608
Lallement R.: 1987,Solar Wind 6, NCAR/TN-306, 651
Leer E., Holzer T.E., Fla T.: 1982,Space Sci. Rev.,33, 161–200
Munro R.H., Jackson B.V.: 1977,Astrophys. J.,213, 874
Osterbart R., Fahr H.J.: 1992,Astron. Astrophys.,264, 260
Pryor W.R., Ajello J.M., Barth C.A.,et al.: 1992,Astrophys. J.,394, 363–377
Quémerais E. and Bertaux J.L.: 1993,Astron. Astrophys.,277, 283
Quémerais E., Lallement R., Bertaux, J.L.: 1993,J. of Geophys. Res.,98, A9, 15199–15210
Quémerais E.: 1993, Ph.D. Thesis, Université Paris VI
Quémerais E., Lallement R. and Bertaux J.L.: 1992,Astron. Astrophys.,265, 806–816
Quémerais E., Sandel B.R., Lallement R. and Bertaux J.L.: 1995,Astron. Astrophys.,299, 249
Richardson J.D., Paularena K.I., Belcher J.W. and Lazarus A.J.: 1994,Geophys. Res. Lett.,21, 14, 1559
Roettger E.E., Feldman P.D., A'Hearn M.F. and Festou M.C.: 1990,Icarus,86, 100
Stewart A.I.F.: 1987,Astron. Astrophys.,187, 369–374
Summanen T., Lallement R., Bertaux J.L. and KyrölÄ E.: 1993,J. Geophys. Res.,98, A8, 13215–13224
Thomas G.E. and Krassa R.F.: 1971,Astron. Astrophys.,11, 218
Thomas G.E. and Bohlin R.: 1972,J. Geophys. Res.,77, 16, 2752–61
Wallis M.K.: 1975,Nature,254, 202
Withbroe G.L., Kohl J.L., Weiser H., Munro R.H.: 1982,Space Science Reviews,33, 17
Witte M., Rosenbauer H., Banaszkiewicz M., Fahr H.J.: 1993,Adv. Space Res.,13, 6, 121
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Bertaux, J.L., Kyrölä, E., Quémerais, E. et al. SWAN: A study of Solar Wind Anisotropies on SOHO with Lyman alpha sky mapping. Sol Phys 162, 403–439 (1995). https://doi.org/10.1007/BF00733435
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DOI: https://doi.org/10.1007/BF00733435