DOI.īroun, J.A.: 1848, Observations in magnetism and meteorology made at Makerstoun in Scotland. DOI.īoller, B.R., Stolov, H.L.: 1970, Kelvin-Helmholtz instability and the semiannual variation of geomagnetic activity. Jr.: 1971, Large-amplitude Alfvén waves in the interplanetary medium, 2. DOI.īaker, D.N., Kanekal, S.G., Pulkkinen, T.I., Blake, J.B.: 1999, Equinoctial and solstitial averages of magnetospheric relativistic electrons: a strong semiannual modulation. DOI.Īlves, M.V., Echer, E., Gonzalez, W.D.: 2006, Geoeffectiveness of corotating interaction regions as measured by Dst index. DOI.Īllen, R.C., Ho, G.C., Mason, G.M., Li, G., Jian, L.K., Vines, S.K., Schwadron, N.A., Joyce, C.J., Bale, S.D., Bonnell, J.W., Case, A.W., Christian, E.R., Cohen, C.M.S., Desai, M.I., Filwett, R., Goetz, K., Harvey, P.R., Hill, M.E., Kasper, J.C., Korreck, K.E., Lario, D., Larson, D., Livi, R., MacDowall, R.J., Malaspina, D.M., McComas, D.J., McNutt, R., Mitchell, D.G., Paulson, K.W., Pulupa, M., Raouafi, N., Stevens, M.L., Whittlesey, P.L., Wiedenbeck, M.: 2021, Radial evolution of a CIR: observations from a nearly radially aligned event between Parker Solar Probe and STEREO-A. On average, SYM-H is strongly associated with the CIR plasma characteristic parameters (anti-correlation coefficient \(r=-0.65\) to −0.89), while the association is weaker for the AE-index ( \(r=0.41\) to 0.67).Īllen, R.C., Lario, D., Odstrcil, D., Ho, G.C., Jian, L.K., Cohen, C.M.S., Badman, S.T., Jones, S.I., Arge, C.N., Mays, M.L., Mason, G.M., Bale, S.D., Bonnell, J.W., Case, A.W., Christian, E.R., Dudok de Wit, T., Goetz, K., Harvey, P.R., Henney, C.J., Hill, M.E., Kasper, J.C., Korreck, K.E., Larson, D., Livi, R., MacDowall, R.J., Malaspina, D.M., McComas, D.J., McNutt, R., Mitchell, D.G., Pulupa, M., Raouafi, N., Schwadron, N., Stevens, M.L., Whittlesey, P.L., Wiedenbeck, M.: 2020, Solar wind streams and stream interaction regions observed by the Parker Solar Probe with corresponding observations at 1 au. CIRs during equinoxes are found to be more geoeffective compared to those during solstices. The geoeffectiveness is found to decrease with the decreasing solar flux. About 30% of the CIRs are found to be geoeffective, causing geomagnetic storms with the peak SYM-H \(\leq -50\) nT 25% caused moderate storms (−50 nT ≥ SYM-H \(>-100\) nT), and 5% caused intense storms (SYM-H \(\leq -100\) nT). The CIR characteristic features exhibit no clear solar-cycle phase dependence. CIRs are characterized by average (median) plasma density of \(\approx 29\) cm −3 ( \(\approx 26\) cm −3), ram pressure of \(\approx 11\) nPa ( \(\approx 9\) nPa), temperature of \(\approx 5\times 10^\) K), and magnetic-field magnitude of \(\approx 15\) nT ( \(\approx 14\) nT). At 1 AU, CIRs are found to be large-scale interplanetary structures with an average (median) duration of \(\approx 26\) hours ( \(\approx 24\) hours) and radial extent of \(\approx 0.31\) AU ( \(\approx 0.27\) AU). The occurrence rate is the maximum during the solar-cycle descending phase ( \(\approx 33\) year −1), followed by occurrences during solar minimum ( \(\approx 24\) year −1), the ascending phase ( \(\approx 22\) year −1), and solar maximum ( \(\approx 11\) year −1). Using solar-wind measurements upstream of Earth, we identified 290 CIRs encountered by Earth during January 2008 through December 2019 (Solar Cycle 24). Over the years, RHESSI documented the huge range in solar flare size, from tiny nanoflares to massive superflares that were tens of thousands of times bigger and more explosive.Corotating interaction regions (CIRs) form in the interaction region between the solar-wind high-speed streams and slow streams, leading to compressed plasma and magnetic fields. These solar events release the energy equivalent of billions of megatons of TNT into the sun’s atmosphere within minutes and can have effects on Earth, including the disruption of electrical systems. From its former perch in low-Earth orbit, the satellite captured images of high-energy electrons that carry a large part of the energy released in solar flares, NASA said.īefore RHESSI, no gamma-ray images or high-energy X-ray images had been taken of solar flares, and data from the spacecraft provided vital clues about the phenomena and their associated coronal mass ejections. The spacecraft was equipped with an imaging spectrometer, which recorded the sun’s X-rays and gamma rays. Webb telescope captures glowing starburst as galaxies collide Shining like a brilliant beacon amidst a sea of galaxies, Arp 220 lights up the night sky in this view from NASA's James Webb Space Telescope.
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