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	<metadata ReferenceType="Journal Article">
		<site>mtc-m16d.sid.inpe.br 806</site>
		<holdercode>{isadg {BR SPINPE} ibi 8JMKD3MGPCW/3DT298S}</holdercode>
		<lastupdate>2010: sid.inpe.br/mtc-m19@80/2009/ administrator</lastupdate>
		<metadatalastupdate>2021: sid.inpe.br/bibdigital@80/2006/ administrator</metadatalastupdate>
		<title>The properties of two solar wind high speed streams and related geomagnetic activity during the declining phase of solar cycle 23</title>
		<size>2175 KiB</size>
		<author>Tsurutani, Bruce T.,</author>
		<author>Echer, Ezequiel,</author>
		<author>Guarnieri, Fernando L.,</author>
		<author>Gonzalez Alarcon, Walter Demétrio,</author>
		<affiliation>CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA</affiliation>
		<affiliation>Instituto Nacional de Pesquisas Espaciais (INPE)</affiliation>
		<affiliation>Universidade do Vale do Paraiba (UNIVAP)</affiliation>
		<affiliation>Instituto Nacional de Pesquisas Espaciais (INPE)</affiliation>
		<journal>Journal of Atmospheric and Solar-Terrestrial Physics</journal>
		<secondarytype>PRE PI</secondarytype>
		<contenttype>External Contribution</contenttype>
		<keywords>High speed solar wind streams, Interplanetary Alfvenicity, Geomagnetic activity, HILDCAAs.</keywords>
		<abstract>Two high speed stream (HSS) solar wind intervals (days 283¨C294 and 314¨C318, 2003, hereafter called Events 1 and 2) during the declining phase of solar cycle 23 have been examined in detail for their interplanetary characteristics and their resultant geomagnetic activity. Event 1 had an associated storm initial phase with peak Dst=+9 nT. This was caused by a high plasma density heliospheric plasma sheet (HPS) which impacted the magnetosphere. The southward component of IMF Bz fluctuations in the corotating interaction regions (CIRs) of both Events 1 and 2 led to peak storm main phases of Dst=&#8722;85 and &#8722;62 nT, respectively. The extended storm ¡°recovery¡± phases were associated with ¦¤B/Bo 1¨C2 Alfv¨¦nic fluctuations in the HSS proper. High-intensity, long-duration, continuous AE (HILDCAA) intervals were present, presumably due to the southward component of the Alfv¨¦n waves. The IMF Bx¨CVx 4-h cross-correlation values were >0.8 in Event 2, and lower, >0.6, in Event 1. The difference in Alfv¨¦nicity between the two HSS events is not understood at present. The IMF Bz 10-min to 3-h variances  and are highest during the CIRs. The normalized variances  during the HSS proper are approximately the same as those for the CIRs. For Event 1, the 1-h IMF  and  are 5.0 nT2 and 1.1¡Á10&#8722;1, respectively. The IMF Bz-AE cross-correlation (c.c.) coefficients during the storm main phase of Event 1 and for 24-h of the HSS of Event 2 give similar results. For the Event 1, a peak c.c. of &#8722;0.4 occurred with a lag of 103 min, and for Event 2 a peak c.c of &#8722;0.38 with a lag of 67 min was obtained. Both c.c. results were sharply peaked. The decay-portion of a HSS prior to Event 1 was characterized by low Np, low Bo and low Alfv¨¦n wave amplitudes. The 1-h IMF  and  were 0.84 nT2 and 2.9¡Á10&#8722;2, respectively. This quiet interplanetary interval led to a quiet geomagnetic activity period (AE<100 nT, Dst +5 nT). On the other hand, what is quite surprising is that this region was the most purely ¡°Alfv¨¦nic¡± interval studied (c.c. of Bx-Vx=0.95).The ¦Å parameter was calculated using both GSE and GSM coordinates. It was found that ¦Å is 30% larger for GSM coordinates. Thus, the major cause of geomagnetic activity during HSSs is the large amplitude Alfv¨¦n waves but not coordinate transformations. Sector polarities (IMF By values) may be a secondary factor. However, other models, like the tilted solar dipole, should be considered as well.</abstract>
		<targetfile>the properties of two solar.pdf</targetfile>
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		<readpermission>deny from all and allow from 150.163</readpermission>
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		<dissemination>WEBSCI; PORTALCAPES; AGU; MGA; COMPENDEX.</dissemination>