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The Fields of Force in the Atmosphere of the Sun


The structure of the solar atmosphere above and sluronllllding sunspots has been Plustrated in a previous article in NATURE.1 Silngle spots often lie at the centre of an apparent vortex resembling a terrestrial tornado or cycloriec soe i times nearly radial in form, more cornmmonly showing marked clockwise or counter-clockwise curvature. Bipolar spots (Fig. 1) are often suyrounded by a field of force similar to that of a bar magnet, though in rany eases the structure is verv different. I havo recenttly discssed the mature of these fields of force,2 but the evidence, which favoured a hydrodynamical rather than an electtro N S Fie. 1.-PIueld of forcE in thi hydrogeh st-rsosphcrr aurroundingt Ang. 21, M C4 T oe ibrditturt cf the, byclrOge-hr lnral Thase I reljlf siurroidig 111 Dor ite e.mgnetl poles. magnetie explanation, was inconclusive, especially in view of the prevalence of the bar margnet type so frequently assoEiated with bipolar spots. This seemed to point to an eleetronnagnetic origin, and the impossibility uf analysing adequately the structure of the hydrogen flocculi in thfese bipolar fields has greatly impeded progress.

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  1. 1

    "Some New Possibilities in Solar Research," NATURE, July 3, 1926, Supp. p. 1.

  2. 2

    "A Test of the Electromagnetic Theory of the Hydrogen Vortices surrounding Sunspots," Communications from the Mount Wilson Observatory, No. 93; Proc. National Academy of Sciences, 11, 691; 1925.

  3. 3

    Contributions from the Mount Wilson Observatory, No. 109 Astrophysical Journal, 43. 347; 1916.

  4. 4

    Contributions from the Mount Wilson Observatory, No. 26 Astrophysical Journal, 28. 100; 1908.

  5. 5

    It should be clearly unlerstood, however, that Fig. 5 represents three successive stages in the inflow of the tip of a prominence, whereas in the cas illusrated in Fig. 4 the tip had already reached a point above the elee of th penumbra before the observations were begun. With a rather wile second slit, nearly the whole length of this curved flocculus (A to C) could be recorded in a single photogrsph, as shown in Fig. 3.

  6. 6

    Astrophysical Journal, 36, 265; 1912.

  7. 7

    "The Forms and Motions of the Solar Prominences," Pub. Yerkes Observatory, 3. part 4; 1925.

  8. 8

    Memoirs Kodaikanal Observatory, 1, part 2; 106.

  9. 9

    See Hale and Nicholson, "The Law of Sunspot Polarity," (Contributions from the Mount Wilson Observatory, No. 300; Astrophysical Journal, 62, 270; 1925.

  10. 10

    "Sunspots as Magnets and the Periodic Reversal of their Polarity," NATURE, Jan. 19, 1924.

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