HeliosphericHeliospheric Observations Observations during during October – November 2003October – November 2003

HeliosphericHeliospheric Observations Observations during during October – November 2003October – November 2003

Hari Om VatsHari Om VatsPhysical Research LaboratoryPhysical Research Laboratory

Ahmedabad 380009 INDIAAhmedabad 380009 INDIA

Email: vats@prl.ernet.inEmail: vats@prl.ernet.in

ICRC meeting, 3 – 10 August 2005, Pune, INDIA Session: SH.3.5

Day number of 2003

100 200 300

Su

nsp

ot

Nu

mb

er

0

50

100

150

200

250

300

350

Day number of 2003

100 200 300

Su

nsp

ot

Are

a (1

0-6 H

em

isp

her

e)

0

1000

2000

3000

4000

5000

6000

Day Number of 2003

100 200 300

So

lar

Rad

io F

lux

(S

FU

)

50

100

150

200

250

300

350Day number of 2003

100 200 300

Fla

re In

dex

0

20

40

60

80

100

120

140

Day Number (from 1-10-2003)

0 10 20 30 40 50 60

Geom

ag

neti

c In

dex

-400

-200

0

200

400

Dst

Ap

Day number (from 1-10-2003)

0 10 20 30 40 50 60

Bz

-10

0

10

20

30

40

50 October – November 2003October – November 2003

Ap and Dst indicies showAp and Dst indicies showevidence of strong evidence of strong geomagnetic activitygeomagnetic activity

Bz is largely positiveBz is largely positiveIt remains so during strong It remains so during strong geomagnetic activitygeomagnetic activity

Bz

-10 0 10 20 30 40 50

Kp

0

2

4

6

8

10

October – November 2003October – November 2003

Bz

0 10 20 30 40 50

Dst

(n

T)

-500

-400

-300

-200

-100

0

100

Bz

-10 -8 -6 -4 -2 0

Dst

(n

T)

-500

-400

-300

-200

-100

0

100

Bz

-10 0 10 20 30 40 50

Dst

(n

T)

-500

-400

-300

-200

-100

0

100

October – November 2003October – November 2003

Solar wind pressure nPa

0.1 1 10

Kp

0

2

4

6

8Solar wind pressure (nPa)

0 5 10 15 20

Dst

-500

-400

-300

-200

-100

0

October – November 2003October – November 2003

IMF (Bz)

-10 -5 0 5 10 15 20

Dst

-150

-100

-50

0

50

IMF (BZ)

-10 -5 0 5 10 15 20

Ap

Ind

ex

0

20

40

60

80

100

120

140

Bastille day eventBastille day event14 July 200014 July 2000

Dst is +ve or low –ve Dst is +ve or low –ve for most of the - Bzfor most of the - Bz

Dst is highly –veDst is highly –vefor + Bzfor + Bz

Ap is high and lowAp is high and lowfor - Bzfor - Bz

Solar Wind Pressure (nPa)

0 10 20 30

Ap

Ind

ex

0

100

200

300

400

Solar Wind Pressure (nPa)

1 10

Kp

Ind

ex

0

2

4

6

8

10

Bastille day eventBastille day event14 July 200014 July 2000

Solar wind pressure (nPa)

0.1 1 10

Geo

mag

net

ic In

dex

Kp

0

1

2

3

4

5

May 4 – 16 1999 (solar wind disappearance event; May 11 – 12)

ConclusionsConclusions

• Sunspot number, area, radio flux and flare index Sunspot number, area, radio flux and flare index show a distinct enhancement during Oct. – Nov. show a distinct enhancement during Oct. – Nov. 2003.2003.

• No apparent correlation with –ve Bz seenNo apparent correlation with –ve Bz seen

• Log of solar wind pressure gives largely linear Log of solar wind pressure gives largely linear relation with Kp Index.relation with Kp Index.

• The slopes of log (nPa) and Kp plots The slopes of log (nPa) and Kp plots 6 Oct.- Nov. 2003 most active period6 Oct.- Nov. 2003 most active period 4 14 July 2000) Bastille day4 14 July 2000) Bastille day 2 May 11 – 12 1999 SW disappearance2 May 11 – 12 1999 SW disappearance

Thank you very muchThank you very much

Solar wind pressure (nPa)

0 5 10 15 20

Dst

-500

-400

-300

-200

-100

0

Solar wind pressure (nPa)

0 10 20 30

Dst

-300

-200

-100

0

October-November, 2003October-November, 2003

Bastille day eventBastille day eventJuly 14, 2000July 14, 2000

Dst seems to have no dependenceDst seems to have no dependenceof solar wind pressureof solar wind pressure

0

2

4

6

8

10

12

14

16

18

20

350 450 550 650 750 850 950

Vmax (kms/sec)

Per

cen

tag

e O

ccu

rren

ce

0

2

4

6

8

10

12

14

16

18

20

2 4 6 8 10 12 14 16 18

Stream Duration (Days)P

erce

nta

ge

Occ

urr

ence

Flare

Flare

Coronal Hole

Coronal Hole

High speed streamsCharacteristcs

DurationVmax

FlareCoronal Hole

Similar

Vats 1992a

CatalogueMavromichalaki

et. al 1988

J uly 1980

5 10 15 20 25 30

Geom

ag

neti

c I

nd

ex

-60

-40

-20

0

20

40

cs -FGS - FGS +

Ap

Dst

Flare Generated Streams with – and + IMF both seem Flare Generated Streams with – and + IMF both seem to generate big geomagnetic storms.to generate big geomagnetic storms.

Coronal hole associated Stream with – IMF seems Coronal hole associated Stream with – IMF seems to generate a mild geomagnetic stormto generate a mild geomagnetic storm.

J uly 1975

5 10 15 20 25 30

Geom

ag

neti

c I

nd

ex

-40

-20

0

20

40

cs -FGS -

cs +

Ap

Dst

Coronal hole associated Streams with – and + IMF generate a mild toCoronal hole associated Streams with – and + IMF generate a mild toStrong geomagnetic storms.Strong geomagnetic storms.

Flare Generated Stream with – IMF generate a strong geomagnetic Flare Generated Stream with – IMF generate a strong geomagnetic Storm.Storm.

Average Vp during the events (km/ sec)

500 600 700 800 900Avera

ge e

nh

an

ced

Ap

du

rin

g t

he e

ven

ts

0

20

40

60

80

100

120

Streams with + IMF

Streams with - IMF

Streams with – and + IMFStreams with – and + IMFgenerate geomagnetic storm.generate geomagnetic storm.

Vp and Ap enhamcement plotVp and Ap enhamcement plothas two slopes with a thresholdhas two slopes with a thresholdat ~850 km/sec.at ~850 km/sec.

Geomagnetic activity enhancement rate (GAER) is defined as an average Geomagnetic activity enhancement rate (GAER) is defined as an average increase in Ap value per unit average increase in the peak solar wind increase in Ap value per unit average increase in the peak solar wind velocity (Vp) during the stream.velocity (Vp) during the stream.

GAER for Vp >850 km/sGAER for Vp >850 km/s0.73 and 0.53 for + and –0.73 and 0.53 for + and –IMF respectivelyIMF respectively

GAER for Vp <850 km/sGAER for Vp <850 km/s0.08 and 0.09 for + and –0.08 and 0.09 for + and –IMF respectivelyIMF respectively

1

3

5

7

2 4 6 8

HS Stream Duration (Days)

Sto

rm D

ura

tio

n (

Day

s)

Coronal Hole

Flare

10

20

30

40

50

60

70

80

90

100

110

400 600 800

Vmax during the events (kms/sec)A

vear

ge

AP

en

han

cem

ent

Coronal Hole

Flare

Geomagnetic effects

Storm durationandMagnitude

Associated with flareand Coronal Holeare quite different.

Flares produce 2.7 timesstronger storms.

Coronal holes producelonger (1.5 times) duration storms

Vats (1992b)

G = 0.64 S – 0.15G = 0.64 S – 0.15

G = 0.42 S – 0.35G = 0.42 S – 0.35

GAER = 0.58GAER = 0.58

GAER = 0.12GAER = 0.12

GAER = 0.07GAER = 0.07

ConclusionsConclusions

• HSS (Flares and coronal holes) enhance geomagnetic activity HSS (Flares and coronal holes) enhance geomagnetic activity irrespective of IMF polarity.irrespective of IMF polarity.

• HSS >850 km/s GAER 0.73 and 0.53 for + and – IMF resply.HSS >850 km/s GAER 0.73 and 0.53 for + and – IMF resply.• HSS <850 km/s GAER 0.08 and 0.09 for + and – IMF resply.HSS <850 km/s GAER 0.08 and 0.09 for + and – IMF resply.• HSS (Flares) produce 2.7 times stronger storms.HSS (Flares) produce 2.7 times stronger storms. • Coronal holes produce longer (1.5 times) duration storms.Coronal holes produce longer (1.5 times) duration storms.• Sunspot number, area, radio flux and flare index show a Sunspot number, area, radio flux and flare index show a

distinct enhancement during Oct. – Nov. 2003.distinct enhancement during Oct. – Nov. 2003.• No correlation with –ve Bz seenNo correlation with –ve Bz seen• Log of solar wind pressure gives largely linear relation with Kp Log of solar wind pressure gives largely linear relation with Kp

Index.Index.• The slope is more (1.5 times) steep during Oct.- Nov. 2003 than The slope is more (1.5 times) steep during Oct.- Nov. 2003 than

that during Bastille day (14 July 2000)that during Bastille day (14 July 2000)