Radiation Environment of the Inner Magnetosphere: Ouiet and Storm - - PowerPoint PPT Presentation

Mikhail Panasyuk

Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University

Radiation Environment of the Inner Magnetosphere: Ouiet and Storm Periods

40000 km

RB SEP GCR

LEO < 1000km

The Earth’s radiation environment at LEO

Near- Earth space radiation environment:

Low inclination

Count rates (arbitrary units) of protons with energy higher of 0.7 MeV and electrons with energy higher than 0.5 MeV for the NASA SAMPEX Satellite in the low earth orbit (LEO) at ~ 600 km altitude.

Near- Earth space radiation environment:

High inclination

Count rates (arbitrary units) of protons with energy higher of 0.7 MeV and electrons with energy higher than 0.5 MeV for the NASA SAMPEX Satellite in the low earth orbit (LEO) at ~ 600 km altitude.

RB

ISS

Altitude, км

SAA

Latitude

R- 16 dosemeter

2 argon ionization chambers with two different plastic shieldings – 1,5 and 3 g/cm2

Onboard MIR station since 1987 till 2000!

South Atlantic Anomaly

Solar minimum - the middle of 90’s Solar maximum – the beginning of 90’s Longitude Longitude

Daily averaged doses rates since 1987

10 20 30 40 50 60 70 80 90 100

2 Январь, 1991 1 Январь, 1993 2 Январь, 1995 1 Январь, 1997 2 Январь, 1999 1 Январь, 2001 2 Январь, 2003 1 Январь, 2005 2 Январь, 2007

Дата

мрад/сутки.. МИР Д1 МИР Д2 МКС Д1 МКС Д2

MIR data since 1991 till 2000

mRad/day Year D1 D2 1991 2000

The strong solar-cycle variation

Daily averaged doses rates since 1960 till 1969

Different spacecrafts h ~ 350 – 400 km, i~ 65o W Solar cycle variation Nuclear test radiation

1960 1970

The first observational result

• f solar sycle variations

at LEO (Vernov, et al, 1972)

The main mechanizm of radiation belt formation

Balance between transport time (radial diffusion from outer RB edge) - τt and loss time - τl For inner belt, say at L< 2

τt>> τl

But there is a local source for inner RB protons – CRAND

High energy cosmic ray particle (H) 100 km

Atmosphere

neutrons

proton

CRAND

Space

electron

0 km

The space-temporal structure of the inner radiation belt will be determined mainly by losses only (for steady-state source) For high energy protons it is ionization losses with residual atmosphere

MIR station radiation doses in the 22nd solar cycle

2.0E-15 4.0E-15 6.0E-15 8.0E-15 1.0E-14 1.2E-14 1.4E-14

Density, [g cm-3]

1991 1993 1995 1997 1999

Year

50 100 150 200 250

F10.7 average

500 1000 1500 2000

Radiation Dose [mRad/month]

Dose D2 Dose D1 MSISE-90 at h=400 km under SSA (-35,-35)

Atmospheric density Solar activity Doses

2000

1999

Solar cycle flux/atmospheric density variations

RB proton (>10 MeV) flux Loss time as a function

• f atmospheric density

variations Solar max Solar activity variations

MIR station radiation doses in the 22nd solar cycle

2.0E-15 4.0E-15 6.0E-15 8.0E-15 1.0E-14 1.2E-14 1.4E-14

Density, [g cm-3]

1991 1993 1995 1997 1999

Year

50 100 150 200 250

F10.7 average

500 1000 1500 2000

Radiation Dose [mRad/month]

Dose D2 Dose D1 MSISE-90 at h=400 km under SSA (-35,-35)

Atmospheric density Solar activity Doses

2000

1999

The same sign for GCR solar cycle variations!

Radiation doses GCR

«MIR» ISS

Murmansk Moscow

Radiation doses vs GCR variations

ISS expected results

2000MAX 2006MIN

ISS radiation puzzle

ISS/Russian module

R-16 in operation since summer of 2000. SRC (4 instruments DB –8) - since summer of 2001.

DB-8 instruments

2 (shielded and unshielded) semiconductor detectors

SRC placements on board ISS

Блок Расположение ДБ-8 №1 Правый борт, за панелью № 410 ДБ -8 №2 Левый борт, за панелью № 244 ДБ -8 №3 Правый борт, за панелью № 447 ДБ -8 №4 Правый борт, за панелью № 435 Р-16 На потолке салона большого диаметра, за панелью № 327

АИ

Правый борт, за панелью № 447

БКР

Правый борт, за панелью № 447

R-16 daily averaged doses rates

10 20 30 40 50 60 70 80 90 100

2 Январь, 1991 1 Январь, 1993 2 Январь, 1995 1 Январь, 1997 2 Январь, 1999 1 Январь, 2001 2 Январь, 2003 1 Январь, 2005 2 Январь, 2007

Дата

мрад/сутки.. МИР Д1 МИР Д2 МКС Д1 МКС Д2

Канал Д1 функцио- нировал до 12 мая 2006 года Канал Д2 функцио- нировал до 9 апреля 2006 года

DB-8 daily averaged doses rates since 2001

10 20 30 40 50 60 70 80 90 100 01 янв 01 01 янв 02 01 янв 03 01 янв 04 31 дек 04 31 дек 05 31 дек 06 31 дек 07

Дата

мрад/сутки. ДБ-8 № 1 ДБ-8 № 4

2001 2007

Radiation doses GCR

«MIR» ISS

Murmansk Moscow

Dynamics of the inner proton radiation zone Losses:

particle interactions with residual atmosphere

Source:

For ~100 MeV protons - CRAND

Balance between losses and “local” source strength

RB Latitude Weak source Strong source

R a d i a t i o n d o s e s G C R

« M I R » I S S

M u r m a n s k M o s c o w

Weak source, strong losses

GCR as a source of SAA protons (CRAND)

Strong source, weak losses Altitude, км

Daily averaged doses rates

300 350 400 450

02.08.2001 18.02.2002 06.09.2002 25.03.2003 11.10.2003 28.04.2004 14.11.2004

Data Altitude, Km

Daily averaged doses rates

ISS altitude since 2001

Salut MIR

ISS

S/C

Solar cycle variations at LEO since 1960

1960 2006

(< 400km)

Conclusions

1.SAA anomaly radiation is the principal source

• f radiation hazard at altitude >350 km
• 2. Long–term variations of radiation doses are dependent

both losses and strengh of source(CRAND)

• f particles during solar cycle
• 3. During very strong SEE epoch from 2001 till 2004

there was a very quite radiation condition onboard ISS (and at LEO)

Storm periods: SEP penetration at low altitudes

SEP penetration at low altitudes

– low-latitude boundary of SEP penetration

Λb

Satellite’s orbit

SEP

October- November’03 Radiation Storm SEP penetration at low altitudes

300 301 302 303 304 305 306 307 308 Дни 2003 1.5 2.0 2.5 3.0 3.5 L

• 1.70
• 1.60
• 1.50
• 1.40
• 1.30
• 1.20
• 1.10
• 1.00
• 0.90
• 0.70
• 0.50
• 0.30
• 0.10
• 0.00

0.10

299 300 301 302 303 304 305 306 307 308 309

Дни 2003

• 400
• 300
• 200
• 100

D s t( н T ) 3 4 5 6 7 L

October- November Radiation Storm

SEP penetration at low altitudes

Meteor-3 data, Skobeltsyn Institute of Nuclear Physics,Applied Geophysical Institute

90 MeV proton’s penetration boundary moves toward the equator accordingly with Dst Dst

Λb ~ 49о

Λb

October- November’03 Radiation Storm

SEP penetration at low altitudes

Coronas-Fdata, Skobeltsyn Institute of Nuclear Physics

Variation of proton penetration boundary during isolated substorm

Substorm activity as a regulator of SEP’s penetration

Radiation Storm of October- November,2003

ISS dosimetry

DB-8

ISS/SRC,R16 data, SINP, IMBP

October- November’ 03 vs October’ 89 Radiation Storms: ISS/R16 data

October,89 October,03 Solar particles dose effect (total): 3070mrad Solar particles dose effect : 140mrad

ISS MIR

5 10 15 20 25 30 35 40 90 180 270 360 Долгота восходящего узла орбиты, градус

Доза за сутки, мГрей .

SPE oct 28 SPE oct 29

Calculated doses fo DB8 in dependence

• f initial longitude of ISS for October, 28,29 event

Calculated ISS doses vs initial orbital parameters

Oct.,28

Longitude

Doses

Storm periods:

• 2. Relativistic electron precipitations

from radiation belts

What’s new in this field?

• 2. Relativistic electron precipitations

from radiation belts

What’s new in this field?

“Tatiana” satellite data Ее>3.5 МэВ)

at ~900 km

8 May Dst=-127 nT 15 May Dst=-263 nT 20 May Dst=-103 nT 5 April Dst=-85 nT 12 April Dst=-70 nT

“Catastrophic” precipitations

• f relativistic electrons

5х1025 electrons during ~8 days

Outer belt:

2х1025 electrons !

Balloon experiments at high latitudes

• R. Myllan, et al

40000 km

SEP GCR

ISS

Conclusions

1.Radiation “quite-time” level at LEO is mainly defined by the balance between the strength of CRAND and losses at SAA; 2.Radiation “ storm-time” level at LEO is mainly defined by SEP’s (>1 MeV) penetration pattern at low latitudes, which is ruled by substorm and storm activity;

• 3. More complex picture one should expect for electron

component which is needed for further study

40000 km

SEP GCR

ISS

Thank you

SRC placements on board ISS

Блок Расположение ДБ-8 №1 Правый борт, за панелью № 410 ДБ -8 №2 Левый борт, за панелью № 244 ДБ -8 №3 Правый борт, за панелью № 447 ДБ -8 №4 Правый борт, за панелью № 435 Р-16 На потолке салона большого диаметра, за панелью № 327

АИ

Правый борт, за панелью № 447

БКР

Правый борт, за панелью № 447

SEP’s doses rates from 2001 till 2003

Dosemeters

24.09.2001, mGrey(mRad) 04.11.2001, mGrey(mRad) 28.10.2003, mGrey(mRad) 29.10.2003, mGrey(mRad) nonshielded

1,65 (165) 2,60 (260) 6,63 (663) 2,02 (202) DB-8 № 1

shielded

0,75 (75) 1,10 (110) 3,19 (319) 1,20 (120)

nonshielded

1,26 (126) 1,14 (114) 2,88 (288) 0,906 (91) DB-8 № 2

shielded

0,80 (80) 0,40 (40) 1,16 (116) 0,49 (49)

nonshielded

0,59 (59) 0,75 (75) 2,20 (220) 0,86 (86) DB-8 № 3

shielded

0,41 (41) 0,39 (39) 1,45 (145) 0,64 (64)

nonshielded

0,19 (19) 0,09 ( 9 ) 0,73 (73) 0,28 (28) DB-8 № 4

shielded

0,14 (14) < 0,04 ( <4 ) 0,60 (60) 0,246 (25)

nonshielded

1,25 (125) 0,60 (60) > 0,60 (>60) 0,40 (40) R-16

shiekded

0,20 (20) 0,10 -0,15 (10) 0,25 -0,30 (25) 0,05 – 0,10 (5)

• 1. The value of doses highly dependent
• n particular place inside ISS
• 2. The value of doses - highly dependent on particular

longitude of ISS during onset of SEP event