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STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 (Bucik et al., AnGeo, 2009)•these two bursts periods show an excess in number of counts beyond 4He mass range compared to the CIR events•the excess appears to be a bit larger in the magnetosphere (Feb 7-8) than in the solar wind (Mar 6-7)
1.is this a special ‘magnetosphere-related acceleration’ on solar wind which leads to the heavy ion enrichment ?2.or other than solar wind population is accelerated ?
SIT-B 40-160 keV
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• these additional counts during the bursts events are considerably reduced above 80 keV!• notice that in CIR histograms species like C, N, O and NeS are not resolved in this energy range (or linear scale effect?)
SIT-B 80-160 keV
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Fig.6 in Opitz et al., JGR, 2014; but G.M. Mason reports in the Aug 13, 2014 e-mail a contamination below 80 keV/n for NeS and Fe boxes.
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But these burst almost disappears above 80 keV !
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• gray – counts from both bursts periods; red – Dec 9 2007 CIR• count excess in 6-12 & 12-20 amu in slide 1 is due to counts in 40-80 keV/n range; in CIRs there are many counts in range 60-160 keV/n which masks this excess in histograms on slide 1• the shape of the 1st excess (6-12 amu) is due toenergy threshold and contains likely 4He ions • the 2nd excess (12-20 amu) should be due 16O• there is also small 3rd peak due to NeS ions• since these bursts are low-energy phenomena we luckily see O and NeS peaks! Therefore the claiming in Opitz paper that enhancements in bursts are seen in C-O range was correct. • for 40-80 keV/n the CIR and bursts histograms are quite similar - implying common seed population (solar wind)?• at higher energies (see last histogram which is almost above the threshold energy for hydrogen ) the H/He ratio in bursts is much different than in the CIR – implying different acceleration processes ?
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• previous CIR histograms in log scale
16O
20Ne-32S
12C
no ‘so’ obvious peaks?
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BACKGROUND
• ~20 min periodic bckg. feature, where:
• 80-160 keV/n 4He counts shifted to higher amu (to C-O range) &
• at higher energies (see 320-640 keV/n) when H counts start to appear, their counts also shifted to higher amu (like 3He)
• such bckg. is not visibleabove 20 amu and for 40-80keV/n – but not sure
because counts are low (next slide checks this for a stronger event)
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• now there are two periods in the background • also this stronger event shows that NeS, Fe & 40-80 keV/n are not much affected by this bckg.
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SIT-B bursts on top of CIR event
• why these bursts coincide with the periodic bckg. increases? But they are not bckg., otherwise they appear always and it’s not the case! Would we see these bursts if SIT-B is working without these periodic failures?
etc.
40-57
57-80
80-113
113-160
160-226
226-320
320-453
453-640
640-905
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… back to the G. Mason ‘s report on contamination < 80 keV/n
• in this event, counts in gray area (40-57 keV) behave differently than rest energy ranges (especially at ~20-40 amu)• Fe peak is not well separated at40-57 but at 57-80 keV/n is separated well
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sunward pointing sensoranti-sunward pointing
101-110 keV SEPT ions
pattern similar to STB
• the bursts pattern on STA until ~300Re (20 Jan) is similar to STB
STEREO-A
STEREO-B
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STB almost at the bow-shock
STA far (300 Re) from the bow shock
• STB shows more isotropic pattern while STA shows strong anisotropy spikes in anti-sunward direction; strong simultaneous spikes #1,2,3,4 arrive from anti-sunward
direction on STA but from sunward (or are more isotropic) on STB – placing their origin at the bow shock?
#1 #2 #3 #4sunward pointing sensoranti-sunward pointing
?
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