Transcript
Page 1: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

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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Page 2: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

• 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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Page 3: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

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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Page 4: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

But these burst almost disappears above 80 keV !

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Page 5: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

• 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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Page 6: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

• previous CIR histograms in log scale

16O

20Ne-32S

12C

no ‘so’ obvious peaks?

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Page 7: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

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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Page 8: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

• 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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Page 9: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

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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Page 10: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

… 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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Page 11: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

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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Page 12: STB CIR events #17,19,20,22 are from period Dec 2007-Feb 2008 ( Bucik  et al.,  AnGeo , 2009)

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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