2009:
185:. In active regions the energy flux is about 10 erg cmsec, in the quiet Sun it is roughly 8 10 – 10 erg cmsec, and in coronal holes 5 10 - 8 10 erg cmsec, including the losses due to the solar wind. The required power is a small fraction of the total flux irradiated from the Sun, but this energy is enough to maintain the plasma at the temperature of million degrees, since the density is very low and the processes of radiation are different from those occurring in the photosphere, as it is shown in detail in the next section.
194:
123:
2915:
1981:
1995:
2037:
22:
2023:
217:. This radiation is not visible from the Earth because it is filtered by the atmosphere. Before the first rocket missions, the corona could be observed only in white light during the eclipses, while in the last fifty years the solar corona has been photographed in the EUV and X-rays by many satellites (
334:
Some of these spectral lines can be forbidden on the Earth: in fact, collisions between particles can excite ions to metastable states; in a dense gas these ions immediately collide with other particles and so they de-excite with an allowed transition to an intermediate level, while in the corona it
326:
produced by metal ions which had been excited to a superior state by collisional processes. Many spectral lines are emitted by highly ionized atoms, like calcium and iron, which have lost most of their external electrons; these emission lines can be formed only at certain temperatures, and therefore
287:
In an optically-thin plasma the matter is not in thermodynamical equilibrium with the radiation, because collisions between particles and photons are very rare, and, as a matter of fact, the square root mean velocity of photons, electrons, protons and ions is not the same: we should define a
300:
335:
is more probable that this ion remains in its metastable state, until it encounters a photon of the same frequency of the forbidden transition to the lower state. This photon induces the ion to emit with the same frequency by
114:
coming from the solar corona and transition region, where the plasma is optically-thin. On the contrary, in the chromosphere, where the temperature decreases from the photospheric value of 6000 K to the minimum of 4400 K, the
1729:
1848:
1487:
1609:
1361:
1967:
535:
378:: in this case the line width can be used to estimate the macroscopic velocity also on the Sun's surface, but with a great uncertainty. The magnetic field can be measured thanks to the line splitting due to the
1037:: every accelerated charge emits radiation according to classical electrodynamics. This effect gives an appreciable contribution to the continuum spectrum only at the highest temperatures, above 10 MK.
1130:
1241:
has been modeled by many authors but with differences that depend strongly upon the assumed elemental abundances of the plasma, and of course on the atomic parameters and their estimation.
920:
1040:
Taking into account all the dominant radiation processes, including satellite lines from metastable states, the emission of an optically-thin plasma can be expressed more simply as
1244:
In order to calculate the radiative flux from an optically-thin plasma in a convenient analytic form, Rosner et al. (1978) suggested a formula for P(T) (erg cm s) as follows:
40:
350:
in lines of different ions of the same element, temperature and density can be measured with a good approximation: the different states of ionization are regulated by the
1202:
1031:
773:
989:
730:
953:
697:
838:
811:
667:
596:
565:
1239:
1162:
644:
991:
is calculated as the energy emitted per unit volume and time when free electrons are captured from ions to recombine into neutral atoms (dielectronic capture).
620:
2321:
158:. There are strong evidences that even the heating mechanism, responsible for its high temperature of million degrees, is linked to the magnetic field of the
2248:
Gronenschild, E. H. B. M. & Mewe, R. (1978). "Calculated X-radiation from optically thin plasmas. III – Abundance effects on continuum emission".
1617:
1737:
1369:
1495:
1250:
1856:
370:
of velocities at the temperature of line formation (thermal line broadening), while it is often larger than predicted. The widening can be due to
256:
The emitting plasma is almost completely ionized and very light, its density is about 10 - 10 g/cm. Particles are so isolated that almost all the
2008:
414:
177:; actually, part of the energy is irradiated outwards, but approximately the same amount of the energy flux is conducted back towards the
322:, principally emitted from ions which absorb photons of the same frequency of the transition to an upper energy level, coronal lines are
2445:
1164:
depends only on the temperature. All the radiation mechanisms require collision processes and basically depend on the squared density (
367:
2394:
242:
2739:
2425:
58:
2180:
Landini, M.; Monsignori Fossi, B. (1970). "Computation of solar X-ray emission in the region 1-100 Å for Te from 1 MK to 100 MK".
2944:
2895:
2900:
1046:
2698:
2370:
2145:
Withbroe, George L. (1988). "The temperature structure, mass, and energy flow in the corona and inner solar wind".
849:
2876:
359:
273:
2954:
2571:
2103:
182:
103:
2949:
2870:
2713:
2606:
346:
of the corona allows the determination of many physical parameters of the emitting plasma. Comparing the
2766:
2586:
2418:
230:
198:
2850:
2820:
2638:
2455:
2346:
2288:
2257:
2220:
2189:
2154:
841:
733:
155:
193:
2670:
1986:
371:
336:
293:
202:
2756:
2488:
2362:
2336:
1167:
347:
250:
147:
127:
997:
739:
2890:
2805:
2611:
2390:
289:
961:
702:
2596:
2505:
2411:
2354:
2350:
2296:
2261:
2228:
2162:
2000:
928:
672:
319:
311:
303:
296:, but it depends only on those collisional processes which occur in a very rarefied plasma.
269:
816:
789:
649:
574:
543:
2830:
2810:
2785:
2680:
2625:
2601:
2478:
2074:
1215:
1209:
1138:
629:
623:
397:
the radiative recombinations (free-bound radiation) due to the most abundant coronal ions;
281:
218:
2292:
2224:
2193:
2158:
2800:
2780:
2775:
2563:
2468:
2084:
2065:
2055:
2014:
776:
605:
401:
323:
299:
276:, since hot plasmas are present wherever in the Universe: from stellar coronae to thin
122:
2933:
2845:
2840:
2815:
2744:
2734:
2655:
2650:
2645:
2548:
2525:
2510:
2366:
1034:
783:
379:
355:
351:
277:
268:: in other words, the corona is transparent to the radiation and the emission of the
174:
170:
116:
339:. Forbidden transitions from metastable states are often called as satellite lines.
2939:
2918:
2825:
2795:
2790:
2751:
2581:
2576:
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2535:
2515:
2098:
2060:
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343:
210:
178:
151:
135:
107:
99:
76:
146:
images taken by satellites (see the figure on the right taken by the XRT on board
786:. With a good approximation, the number of occupied states at the superior level
2761:
2708:
2703:
2690:
2675:
2660:
2633:
2543:
2497:
2093:
2028:
1724:{\displaystyle P(T)\approx 10^{-10.4}~T^{-2}~~~~~~(10^{5.4}<T<10^{5.75}K)}
315:
265:
166:
139:
84:
1843:{\displaystyle P(T)\approx 10^{-21.94}~~~~~~~~~~~(10^{5.75}<T<10^{6.3}K)}
1482:{\displaystyle P(T)\approx 10^{-31}~T^{2}~~~~~~~~~(10^{4.6}<T<10^{4.9}K)}
2835:
2665:
2473:
2463:
2358:
2117:
2112:
1976:
1604:{\displaystyle P(T)\approx 10^{-21.2}~~~~~~~~~~~~(10^{4.9}<T<10^{5.4}K)}
1356:{\displaystyle P(T)\approx 10^{-21.85}~~~~~~~~~~~(10^{4.3}<T<10^{4.6}K)}
375:
363:
91:
1962:{\displaystyle P(T)\approx 10^{-17.73}~T^{-2/3}~~~(10^{6.3}<T<10^{7}K)}
1204:). The integral of the squared density along the line of sight is called the
699:
the coefficient of collisional de-excitation relative to the ion transition,
2718:
2591:
2386:
568:
111:
72:
390:
The most important processes of radiation for an optically-thin plasma are
288:
temperature for each of these particle populations. The result is that the
408:
Therefore, the radiative flux can be expressed as the sum of three terms:
2860:
2341:
646:
the frequency of the emitted radiation corresponding to the energy jump
394:
the emission in resonance lines of ionized metals (bound-bound emission);
328:
87:
2520:
530:{\displaystyle L_{r}=n_{e}\sum n_{l}C_{lk}h\nu _{lk}+L_{rec}+L_{brems}}
257:
374:, when collisions between particles are frequent, or it can be due to
1033:
is due to the electron scattering by protons and ions because of the
272:
is optically-thin. The Sun's atmosphere is not the unique example of
238:
226:
222:
214:
143:
2301:
2276:
2233:
2208:
2166:
2022:
331:
is sufficient to determine the temperature of the emitting plasma.
298:
246:
192:
121:
205:
with the same radiative flux of the solar spectrum (yellow area).
2855:
840:
are given by the equilibrium between collisional excitation and
234:
2407:
2434:
2079:
599:
261:
159:
95:
15:
2049:
2403:
110:), and, in particular, the processes of production of the
264:'s surface without interacting with the matter above the
955:
is the transition probability of spontaneous emission.
36:
813:
and the number of states at the inferior energy level
782:
The first term is due to the emission in every single
1859:
1740:
1620:
1498:
1372:
1253:
1218:
1170:
1141:
1049:
1000:
964:
931:
852:
819:
792:
742:
705:
675:
652:
632:
608:
577:
546:
417:
358:
gives a good measurement of the velocities along the
280:. These stellar environments are the subject of the
2883:
2869:
2727:
2689:
2624:
2562:
2534:
2496:
2487:
2454:
31:
may be too technical for most readers to understand
1961:
1842:
1723:
1603:
1481:
1355:
1233:
1196:
1156:
1124:
1025:
983:
947:
914:
832:
805:
767:
724:
691:
661:
638:
614:
590:
559:
529:
138:extends much further than a solar radius from the
2275:Rosner, R.; Tucker, W. H.; Vaiana, G. S. (1978).
1125:{\displaystyle L_{r}=n_{e}n_{H}P(T)~~{W~m^{-3}}}
142:and looks very complex and inhomogeneous in the
2419:
8:
915:{\displaystyle n_{l}n_{e}C_{lu}=n_{u}A_{ul}}
400:for very high temperatures above 10 MK, the
292:does not fit the spectral distribution of a
2250:The Astrophysical Journal Supplement Series
2213:The Astrophysical Journal Supplement Series
2493:
2426:
2412:
2404:
209:The electromagnetic waves coming from the
189:Processes of radiation of the solar corona
126:The Sun in the soft X-rays as seen by the
119:is about 1, and the radiation is thermal.
2340:
2300:
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1947:
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474:
458:
448:
435:
422:
416:
201:of the Sun. The grey area represents the
59:Learn how and when to remove this message
43:, without removing the technical details.
2277:"Dynamics of the quiescent solar corona"
362:but not in the perpendicular plane. The
2137:
169:irradiated from the corona changes in
2209:"Soft X-ray spectrum of a hot plasma"
2207:Raymond, J. C.; Smith, B. W. (1977).
150:). The structure and dynamics of the
130:X-ray Telescope (XRT) on 15 Oct 2009.
41:make it understandable to non-experts
7:
2322:"X-ray astronomy of stellar coronae"
81:radiative losses of the solar corona
2383:Radiation processes in Astrophysics
14:
2914:
2913:
2035:
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2007:
1993:
1979:
20:
1956:
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1350:
1315:
1263:
1257:
1228:
1222:
1151:
1145:
1092:
1086:
386:Optically-thin plasma emission
368:Maxwell–Boltzmann distribution
1:
2896:List of heliophysics missions
327:their individuation in solar
2901:Category:Missions to the Sun
98:(traditionally divided into
1197:{\displaystyle n_{e}=n_{H}}
2971:
213:are emitted mainly in the
173:, in the quiet Sun and in
2909:
2877:G-type main-sequence star
2441:
2359:10.1007/s00159-004-0023-2
2281:The Astrophysical Journal
2147:The Astrophysical Journal
1026:{\displaystyle L_{brems}}
768:{\displaystyle L_{brems}}
732:the radiative losses for
2740:In mythology and culture
2351:2004A&ARv..12...71G
2262:1978A&AS...32..283G
2104:Solar transition region
984:{\displaystyle L_{rec}}
725:{\displaystyle L_{rec}}
2607:Supra-arcade downflows
1963:
1844:
1725:
1605:
1483:
1357:
1235:
1198:
1158:
1126:
1027:
985:
949:
948:{\displaystyle A_{lu}}
916:
834:
807:
769:
726:
693:
692:{\displaystyle C_{lk}}
663:
640:
616:
592:
561:
531:
307:
306:in the solar spectrum.
206:
131:
2945:Emission spectroscopy
2587:Coronal mass ejection
2381:Tucker W. H. (1977).
1964:
1845:
1726:
1606:
1484:
1358:
1236:
1208:and is often used in
1199:
1159:
1127:
1028:
986:
950:
917:
835:
833:{\displaystyle n_{l}}
808:
806:{\displaystyle n_{u}}
770:
727:
694:
664:
662:{\displaystyle h\nu }
641:
617:
593:
591:{\displaystyle n_{k}}
562:
560:{\displaystyle n_{e}}
532:
404:(free-free emission).
366:should depend on the
302:
199:effective temperature
196:
154:are dominated by the
125:
2851:Standard solar model
2821:Solar radio emission
2639:List of solar cycles
2329:Astron Astrophys Rev
1857:
1738:
1618:
1496:
1370:
1251:
1234:{\displaystyle P(T)}
1216:
1168:
1157:{\displaystyle P(T)}
1139:
1047:
998:
962:
929:
850:
842:spontaneous emission
817:
790:
740:
734:plasma recombination
703:
673:
650:
639:{\displaystyle \nu }
630:
606:
575:
544:
415:
181:, through the steep
156:solar magnetic field
2671:Magnetic switchback
2293:1978ApJ...220..643R
2225:1977ApJS...35..419R
2194:1970MmSAI..41..467L
2159:1988ApJ...325..442W
1987:Solar System portal
372:pressure broadening
337:stimulated emission
294:blackbody radiation
203:blackbody radiation
2861:Sunlight radiation
2456:Internal structure
1959:
1840:
1721:
1601:
1479:
1353:
1231:
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1154:
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981:
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912:
830:
803:
765:
722:
689:
659:
636:
612:
588:
557:
527:
308:
207:
132:
90:from the external
83:, it is meant the
2927:
2926:
2891:Solar observatory
2806:Solar observation
2704:Termination shock
2620:
2619:
2572:Transition region
2128:
2127:
1920:
1917:
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1890:
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1299:
1296:
1293:
1290:
1287:
1284:
1107:
1100:
1097:
615:{\displaystyle h}
571:per unit volume,
567:is the number of
290:emission spectrum
183:transition region
104:transition region
69:
68:
61:
2962:
2917:
2916:
2506:Supergranulation
2494:
2428:
2421:
2414:
2405:
2400:
2377:
2375:
2369:. Archived from
2344:
2342:astro-ph/0406661
2326:
2320:Güdel M (2004).
2307:
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2017:
2012:
2011:
2003:
2001:Astronomy portal
1998:
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1982:
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1471:
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1206:emission measure
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1192:
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1032:
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958:The second term
954:
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943:
921:
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637:
621:
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602:number density,
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558:
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501:
500:
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452:
440:
439:
427:
426:
320:absorption lines
314:coming from the
312:Fraunhofer lines
304:Fraunhofer lines
64:
57:
53:
50:
44:
24:
23:
16:
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2955:X-ray astronomy
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2929:
2928:
2923:
2905:
2879:
2865:
2831:Solar telescope
2811:Solar phenomena
2786:Solar astronomy
2723:
2685:
2681:Helioseismology
2616:
2602:Helmet streamer
2558:
2530:
2483:
2479:Convection zone
2450:
2437:
2432:
2397:
2380:
2373:
2335:(2–3): 71–237.
2324:
2319:
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2311:
2310:
2274:
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2269:
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2134:
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2075:X-ray astronomy
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1444:
1404:
1388:
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1337:
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1248:
1214:
1213:
1212:. The function
1210:X-ray astronomy
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1136:
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1001:
996:
995:
994:The third term
965:
960:
959:
932:
927:
926:
899:
889:
873:
863:
853:
848:
847:
820:
815:
814:
793:
788:
787:
743:
738:
737:
706:
701:
700:
676:
671:
670:
648:
647:
628:
627:
624:Planck constant
604:
603:
578:
573:
572:
547:
542:
541:
505:
486:
470:
454:
444:
431:
418:
413:
412:
388:
282:X-ray astronomy
221:5, 6, 7, 8, 9,
191:
65:
54:
48:
45:
37:help improve it
34:
25:
21:
12:
11:
5:
2968:
2966:
2958:
2957:
2952:
2947:
2942:
2932:
2931:
2925:
2924:
2922:
2921:
2910:
2907:
2906:
2904:
2903:
2898:
2893:
2887:
2885:
2881:
2880:
2875:
2873:
2871:Spectral class
2867:
2866:
2864:
2863:
2858:
2853:
2848:
2843:
2838:
2833:
2828:
2823:
2818:
2813:
2808:
2803:
2801:Solar neutrino
2798:
2793:
2788:
2783:
2781:Solar activity
2778:
2776:Sun in fiction
2773:
2772:
2771:
2770:
2769:
2754:
2749:
2748:
2747:
2742:
2731:
2729:
2725:
2724:
2722:
2721:
2716:
2711:
2706:
2701:
2695:
2693:
2687:
2686:
2684:
2683:
2678:
2673:
2668:
2663:
2658:
2653:
2648:
2643:
2642:
2641:
2630:
2628:
2622:
2621:
2618:
2617:
2615:
2614:
2612:Alfvén surface
2609:
2604:
2599:
2594:
2589:
2584:
2579:
2574:
2568:
2566:
2560:
2559:
2557:
2556:
2551:
2546:
2540:
2538:
2532:
2531:
2529:
2528:
2523:
2518:
2513:
2508:
2502:
2500:
2491:
2485:
2484:
2482:
2481:
2476:
2471:
2469:Radiation zone
2466:
2460:
2458:
2452:
2451:
2449:
2448:
2442:
2439:
2438:
2433:
2431:
2430:
2423:
2416:
2408:
2402:
2401:
2396:978-0262700108
2395:
2378:
2376:on 2011-08-11.
2315:
2312:
2309:
2308:
2302:10.1086/155949
2267:
2240:
2234:10.1086/190486
2199:
2172:
2167:10.1086/166015
2136:
2135:
2133:
2130:
2126:
2125:
2121:
2120:
2115:
2108:
2107:
2106:
2101:
2096:
2089:
2088:
2087:
2082:
2077:
2070:
2069:
2068:
2066:Plasma physics
2063:
2058:
2056:Spectral lines
2048:
2047:
2046:
2032:
2018:
2015:Physics portal
2004:
1990:
1974:
1971:
1970:
1969:
1958:
1955:
1950:
1946:
1942:
1939:
1936:
1931:
1927:
1923:
1909:
1905:
1901:
1898:
1894:
1885:
1882:
1878:
1874:
1871:
1868:
1865:
1862:
1851:
1850:
1839:
1836:
1831:
1827:
1823:
1820:
1817:
1812:
1808:
1804:
1766:
1763:
1759:
1755:
1752:
1749:
1746:
1743:
1732:
1731:
1720:
1717:
1712:
1708:
1704:
1701:
1698:
1693:
1689:
1685:
1662:
1659:
1655:
1646:
1643:
1639:
1635:
1632:
1629:
1626:
1623:
1612:
1611:
1600:
1597:
1592:
1588:
1584:
1581:
1578:
1573:
1569:
1565:
1524:
1521:
1517:
1513:
1510:
1507:
1504:
1501:
1490:
1489:
1478:
1475:
1470:
1466:
1462:
1459:
1456:
1451:
1447:
1443:
1411:
1407:
1398:
1395:
1391:
1387:
1384:
1381:
1378:
1375:
1364:
1363:
1352:
1349:
1344:
1340:
1336:
1333:
1330:
1325:
1321:
1317:
1279:
1276:
1272:
1268:
1265:
1262:
1259:
1256:
1230:
1227:
1224:
1221:
1191:
1187:
1183:
1178:
1174:
1153:
1150:
1147:
1144:
1133:
1132:
1118:
1115:
1111:
1104:
1094:
1091:
1088:
1085:
1080:
1076:
1070:
1066:
1062:
1057:
1053:
1020:
1017:
1014:
1011:
1008:
1004:
978:
975:
972:
968:
942:
939:
935:
923:
922:
909:
906:
902:
896:
892:
888:
883:
880:
876:
870:
866:
860:
856:
827:
823:
800:
796:
779:contribution.
777:bremsstrahlung
762:
759:
756:
753:
750:
746:
719:
716:
713:
709:
686:
683:
679:
658:
655:
635:
611:
585:
581:
554:
550:
538:
537:
524:
521:
518:
515:
512:
508:
504:
499:
496:
493:
489:
485:
480:
477:
473:
469:
464:
461:
457:
451:
447:
443:
438:
434:
430:
425:
421:
406:
405:
402:bremsstrahlung
398:
395:
387:
384:
324:emission lines
278:galactic halos
260:can leave the
190:
187:
171:active regions
67:
66:
28:
26:
19:
13:
10:
9:
6:
4:
3:
2:
2967:
2956:
2953:
2951:
2950:Space plasmas
2948:
2946:
2943:
2941:
2938:
2937:
2935:
2920:
2912:
2911:
2908:
2902:
2899:
2897:
2894:
2892:
2889:
2888:
2886:
2882:
2878:
2874:
2872:
2868:
2862:
2859:
2857:
2854:
2852:
2849:
2847:
2846:Space weather
2844:
2842:
2841:Space climate
2839:
2837:
2834:
2832:
2829:
2827:
2824:
2822:
2819:
2817:
2816:Solar physics
2814:
2812:
2809:
2807:
2804:
2802:
2799:
2797:
2794:
2792:
2789:
2787:
2784:
2782:
2779:
2777:
2774:
2768:
2765:
2764:
2763:
2760:
2759:
2758:
2755:
2753:
2750:
2746:
2745:Lunar eclipse
2743:
2741:
2738:
2737:
2736:
2733:
2732:
2730:
2726:
2720:
2717:
2715:
2712:
2710:
2707:
2705:
2702:
2700:
2699:Current sheet
2697:
2696:
2694:
2692:
2688:
2682:
2679:
2677:
2674:
2672:
2669:
2667:
2664:
2662:
2659:
2657:
2656:Solar minimum
2654:
2652:
2651:Solar maximum
2649:
2647:
2646:Active region
2644:
2640:
2637:
2636:
2635:
2632:
2631:
2629:
2627:
2623:
2613:
2610:
2608:
2605:
2603:
2600:
2598:
2595:
2593:
2590:
2588:
2585:
2583:
2580:
2578:
2575:
2573:
2570:
2569:
2567:
2565:
2561:
2555:
2552:
2550:
2547:
2545:
2542:
2541:
2539:
2537:
2533:
2527:
2526:Ellerman bomb
2524:
2522:
2519:
2517:
2514:
2512:
2509:
2507:
2504:
2503:
2501:
2499:
2495:
2492:
2490:
2486:
2480:
2477:
2475:
2472:
2470:
2467:
2465:
2462:
2461:
2459:
2457:
2453:
2447:
2444:
2443:
2440:
2436:
2429:
2424:
2422:
2417:
2415:
2410:
2409:
2406:
2398:
2392:
2388:
2384:
2379:
2372:
2368:
2364:
2360:
2356:
2352:
2348:
2343:
2338:
2334:
2330:
2323:
2318:
2317:
2313:
2303:
2298:
2294:
2290:
2286:
2282:
2278:
2271:
2268:
2263:
2259:
2255:
2251:
2244:
2241:
2235:
2230:
2226:
2222:
2218:
2214:
2210:
2203:
2200:
2195:
2191:
2187:
2183:
2176:
2173:
2168:
2164:
2160:
2156:
2152:
2148:
2141:
2138:
2131:
2124:
2119:
2116:
2114:
2111:
2110:
2109:
2105:
2102:
2100:
2097:
2095:
2092:
2091:
2090:
2086:
2083:
2081:
2078:
2076:
2073:
2072:
2071:
2067:
2064:
2062:
2059:
2057:
2054:
2053:
2052:
2051:
2044:
2033:
2030:
2024:
2019:
2016:
2010:
2005:
2002:
1991:
1988:
1977:
1972:
1953:
1948:
1944:
1940:
1937:
1934:
1929:
1925:
1907:
1903:
1899:
1896:
1892:
1883:
1880:
1876:
1872:
1866:
1860:
1853:
1852:
1834:
1829:
1825:
1821:
1818:
1815:
1810:
1806:
1764:
1761:
1757:
1753:
1747:
1741:
1734:
1733:
1715:
1710:
1706:
1702:
1699:
1696:
1691:
1687:
1660:
1657:
1653:
1644:
1641:
1637:
1633:
1627:
1621:
1614:
1613:
1595:
1590:
1586:
1582:
1579:
1576:
1571:
1567:
1522:
1519:
1515:
1511:
1505:
1499:
1492:
1491:
1473:
1468:
1464:
1460:
1457:
1454:
1449:
1445:
1409:
1405:
1396:
1393:
1389:
1385:
1379:
1373:
1366:
1365:
1347:
1342:
1338:
1334:
1331:
1328:
1323:
1319:
1277:
1274:
1270:
1266:
1260:
1254:
1247:
1246:
1245:
1242:
1225:
1219:
1211:
1207:
1189:
1185:
1181:
1176:
1172:
1148:
1142:
1116:
1113:
1109:
1102:
1089:
1083:
1078:
1074:
1068:
1064:
1060:
1055:
1051:
1043:
1042:
1041:
1038:
1036:
1035:Coulomb force
1018:
1015:
1012:
1009:
1006:
1002:
992:
976:
973:
970:
966:
956:
940:
937:
933:
907:
904:
900:
894:
890:
886:
881:
878:
874:
868:
864:
858:
854:
846:
845:
844:
843:
825:
821:
798:
794:
785:
784:spectral line
780:
778:
760:
757:
754:
751:
748:
744:
735:
717:
714:
711:
707:
684:
681:
677:
656:
653:
633:
625:
609:
601:
583:
579:
570:
552:
548:
522:
519:
516:
513:
510:
506:
502:
497:
494:
491:
487:
483:
478:
475:
471:
467:
462:
459:
455:
449:
445:
441:
436:
432:
428:
423:
419:
411:
410:
409:
403:
399:
396:
393:
392:
391:
385:
383:
381:
380:Zeeman effect
377:
373:
369:
365:
361:
360:line of sight
357:
356:Doppler shift
353:
352:Saha equation
349:
345:
340:
338:
332:
330:
325:
321:
317:
313:
305:
301:
297:
295:
291:
285:
283:
279:
275:
271:
267:
263:
259:
254:
252:
248:
244:
240:
236:
232:
228:
224:
220:
216:
212:
204:
200:
195:
188:
186:
184:
180:
176:
175:coronal holes
172:
168:
163:
161:
157:
153:
149:
145:
141:
137:
129:
124:
120:
118:
117:optical depth
113:
109:
105:
101:
97:
93:
89:
86:
82:
78:
74:
63:
60:
52:
42:
38:
32:
29:This article
27:
18:
17:
2826:Solar System
2796:Solar energy
2791:Solar dynamo
2752:Heliophysics
2582:Coronal loop
2577:Coronal hole
2554:Moreton wave
2536:Chromosphere
2382:
2371:the original
2332:
2328:
2314:Bibliography
2284:
2280:
2270:
2253:
2249:
2243:
2216:
2212:
2202:
2185:
2181:
2175:
2150:
2146:
2140:
2122:
2099:Chromosphere
2061:Spectroscopy
2043:Space portal
1243:
1205:
1134:
1039:
993:
957:
924:
781:
539:
407:
389:
344:Spectroscopy
341:
333:
309:
286:
274:X-ray source
255:
211:solar corona
208:
179:chromosphere
164:
133:
100:chromosphere
80:
77:astrophysics
70:
55:
46:
30:
2884:Exploration
2762:Solar deity
2709:Heliosheath
2691:Heliosphere
2661:Wolf number
2634:Solar cycle
2498:Photosphere
2287:: 643–665.
2256:: 283–305.
2219:: 419–439.
2153:: 442–467.
2094:Photosphere
2029:Star portal
316:photosphere
266:photosphere
167:energy flux
140:photosphere
85:energy flux
2934:Categories
2836:Solar time
2757:In culture
2714:Heliopause
2666:Solar wind
2597:Prominence
2489:Atmosphere
2474:Tachocline
2132:References
2118:Nanoflares
2113:Solar wind
376:turbulence
364:line width
310:While the
92:atmosphere
49:March 2011
2719:Bow shock
2626:Variation
2592:Nanoflare
2387:MIT Press
2367:119509015
2182:Mem. SAIT
1897:−
1881:−
1873:≈
1762:−
1754:≈
1658:−
1642:−
1634:≈
1520:−
1512:≈
1394:−
1386:≈
1275:−
1267:≈
1114:−
657:ν
634:ν
569:electrons
472:ν
442:∑
348:intensity
112:radiation
73:astronomy
2919:Category
2188:: 467L.
1973:See also
88:radiated
2735:Eclipse
2728:Related
2549:Spicule
2521:Sunspot
2516:Faculae
2511:Granule
2435:The Sun
2347:Bibcode
2289:Bibcode
2258:Bibcode
2221:Bibcode
2190:Bibcode
2155:Bibcode
925:where
329:spectra
258:photons
219:Pioneer
94:of the
75:and in
35:Please
2564:Corona
2393:
2365:
2123:
2085:Corona
1919:
1916:
1913:
1889:
1800:
1797:
1794:
1791:
1788:
1785:
1782:
1779:
1776:
1773:
1770:
1681:
1678:
1675:
1672:
1669:
1666:
1650:
1561:
1558:
1555:
1552:
1549:
1546:
1543:
1540:
1537:
1534:
1531:
1528:
1439:
1436:
1433:
1430:
1427:
1424:
1421:
1418:
1415:
1402:
1313:
1310:
1307:
1304:
1301:
1298:
1295:
1292:
1289:
1286:
1283:
1135:where
1106:
1099:
1096:
540:where
354:. The
270:plasma
251:Hinode
239:Yohkoh
227:Skylab
223:Helios
215:X-rays
152:corona
148:Hinode
144:X-rays
136:corona
128:Hinode
108:corona
79:, for
2676:Flare
2544:Plage
2374:(PDF)
2363:S2CID
2337:arXiv
2325:(PDF)
1884:17.73
1765:21.94
1278:21.85
247:TRACE
2856:Star
2767:List
2464:Core
2446:List
2391:ISBN
1941:<
1935:<
1822:<
1816:<
1811:5.75
1711:5.75
1703:<
1697:<
1645:10.4
1583:<
1577:<
1523:21.2
1461:<
1455:<
1335:<
1329:<
775:the
736:and
622:the
598:the
342:The
318:are
243:SOHO
235:NIXT
197:The
165:The
134:The
106:and
2940:Sun
2355:doi
2297:doi
2285:220
2229:doi
2163:doi
2151:325
2080:Sun
1930:6.3
1830:6.3
1692:5.4
1591:5.4
1572:4.9
1469:4.9
1450:4.6
1343:4.6
1324:4.3
626:,
600:ion
262:Sun
253:).
231:SMM
160:Sun
96:Sun
71:In
39:to
2936::
2389:.
2385:.
2361:.
2353:.
2345:.
2333:12
2331:.
2327:.
2295:.
2283:.
2279:.
2254:32
2252:.
2227:.
2217:35
2215:.
2211:.
2186:41
2184:.
2161:.
2149:.
1945:10
1926:10
1877:10
1826:10
1807:10
1758:10
1707:10
1688:10
1638:10
1587:10
1568:10
1516:10
1465:10
1446:10
1397:31
1390:10
1339:10
1320:10
1271:10
669:,
382:.
284:.
249:,
245:,
241:,
237:,
233:,
229:,
225:,
162:.
102:,
2427:e
2420:t
2413:v
2399:.
2357::
2349::
2339::
2305:.
2299::
2291::
2264:.
2260::
2237:.
2231::
2223::
2196:.
2192::
2169:.
2165::
2157::
1957:)
1954:K
1949:7
1938:T
1922:(
1908:3
1904:/
1900:2
1893:T
1870:)
1867:T
1864:(
1861:P
1838:)
1835:K
1819:T
1803:(
1751:)
1748:T
1745:(
1742:P
1719:)
1716:K
1700:T
1684:(
1661:2
1654:T
1631:)
1628:T
1625:(
1622:P
1599:)
1596:K
1580:T
1564:(
1509:)
1506:T
1503:(
1500:P
1477:)
1474:K
1458:T
1442:(
1410:2
1406:T
1383:)
1380:T
1377:(
1374:P
1351:)
1348:K
1332:T
1316:(
1264:)
1261:T
1258:(
1255:P
1229:)
1226:T
1223:(
1220:P
1190:H
1186:n
1182:=
1177:e
1173:n
1152:)
1149:T
1146:(
1143:P
1117:3
1110:m
1103:W
1093:)
1090:T
1087:(
1084:P
1079:H
1075:n
1069:e
1065:n
1061:=
1056:r
1052:L
1019:s
1016:m
1013:e
1010:r
1007:b
1003:L
977:c
974:e
971:r
967:L
941:u
938:l
934:A
908:l
905:u
901:A
895:u
891:n
887:=
882:u
879:l
875:C
869:e
865:n
859:l
855:n
826:l
822:n
799:u
795:n
761:s
758:m
755:e
752:r
749:b
745:L
718:c
715:e
712:r
708:L
685:k
682:l
678:C
654:h
610:h
584:k
580:n
553:e
549:n
523:s
520:m
517:e
514:r
511:b
507:L
503:+
498:c
495:e
492:r
488:L
484:+
479:k
476:l
468:h
463:k
460:l
456:C
450:l
446:n
437:e
433:n
429:=
424:r
420:L
62:)
56:(
51:)
47:(
33:.
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