CMEs and SEPs NatGopalswamy

SolarPhysicsLaboratoryNASA/GSFC

nat.gopalswamy@nasa.gov

2017CCMCBootcamp,TuesdayJune6

Overview

• WhataresolarenergeLcparLcleevents?• CoronalmassejecLons(CMEs)andSEPs• BriefHistory• Radioburstsandshocks• ProperLesofSEP-producingCMEs

What are Energetic Particles? •  Speedof2MKprotons:129km/s=4.3e-4c[√(kT/m)];T=2MK;εth=175eV•  Speedof2MKelectrons:5547km/s=0.018cc=speedoflight;m=mass•  2MKcorrespondstoanenergyof175eV•  NonthermalparLclesareenergeLc:V>>Vthorε>>εth•  ElectronsKeVto100sofMeV,protonsofkeVtotensofGeVfromtheSun(1GeVprotonshaveaspeedof~0.875c=260,000km/s)

•  ElectronsandionsaredetectedbyparLcledetectors;electronsarealsoinferredfromtheirnonthermalradioemission

•  EventsinvolvingemissionofnonthermalparLclesareknownassolarenergeLcparLcle(SEP)events

•  Spaceweathercommunityalsousesthetermsolarprotonevents(SPEs)tospecificallyrefertoenergeLcprotons

CMEs, Flares, SEPs

SOHO/LASCOandEIT hjp://cdaw.gsfc.nasa.gov

1-8Å

0.5-4Å

Yohkoh/SXT

N10W77

Image Degradation due to Particle Impact

3.85Rs 5.04Rs 6.08Rs

44min

4Dayslater

1-AUshock11/106UT

SEP Intensity, Energy Range, Spectrum FluenceSpectrum

Intensity Spectrum

Double Whammy: Geomagnetic Storms & SEPs

TwohaloCMEs:10/28and10/292003

SOHO/LASCO

NORMAL

STORM

Transformeroilheatedby10oinSweden;50,000peopleinMalmohadpowerblackout

SomeLmeserupLonsoccurinquicksuccessionmaintainingelevatedlevelofparLcleradiaLonGopalswamyetal.2005

General Time Profiles of SEP Events

•  OnsetplateauduetowavestrappingparLcles•  Peakwhenshockarrivesatthedetector•  Reservoirbehindtheshock

Protons mostly enter through the magnetotail and precipitate in the polar caps

GOES

About 14% of Earth is affected during solar proton events. •  Changeinionospheric

conducLvity•  OzonedepleLon•  RadiaLonbelttrappingandsatelliteanomalies

0

20

40

60

80

100

Alti

tude

(km

)

Troposphere

Stratosphere

Mesosphere

Alti

tude

(mile

s)

10

0

20

30

40

50

60 1 MeV proton

10 MeV proton

100 MeV proton

1 GeV proton

~2 GeV proton

GOES provides Proton flux for >1 MeV to >100 MeV

Thermosphere

ParLcleshittheairplanematerialandproducesecondaries,whichaffectcrewandpassengersinpolarroute

11-14km

MARIE: The Martian Radiation Environment Experiment

The MARIE instrument on Mars Odyssey observed the radiation levels on the way to Mars and in orbit, so that future mission designers could plan the trips of human explorers to Mars.

One of the October 2003 SEP events rendered MARIE inoperative. It is ironic, as MARIE was designed to measure the radiation environment at Mars.

Radiation Assessment Detector (RAD) on board the Curiosity rover (Mars Science Laboratory) that a 360-day round trip would add a dosage of ~660 mSv. (Zeitlin et al. 2013)

This is ~66% of astronaut’s entire career exposure limit (1000 mSv)

Mars Odyssey

Nozomi

Curiosity provides Radiation info for a Mars Trip

RadiaLonAssessmentDetectoronMarsScienceLaboratory(RAD/MSL)

RADmountedonthetopdeckofCuriosityrover

DatacollecLon:6December2011to14July20121.84mSv/dayduetoGCRsTotal:660mSv;5.4%duetoSEPs

Forbush (1946) Phys. Rev. Lett.

25 July 46 GLE Flare

Scott E. Forbush (1904-1984) a solar flare (bright chromospheric eruption) Forbushdecrease(1937)

Forbush Decrease, SEPs

N07E03

High Velocity Magnetized Plasma from the Sun

“…webelievethesePioneerVresultsprovidethemostdirectevidencetodatefortheexistenceofconducLnggasejectedathighvelocityfromsolarflares”

Fan,Meyer,Simpson,1960PhysRevLej

Pioneer 5 launch: 3/11/1960

50nT

FD

>75MeVparLcles

Radio Bursts Reveal Matter Leaving the Sun

Ruby Payne-Scott 1912 – 1981

The whole pattern drifts; 140 MHz in 6 min ! df/dt = 0.4 MHz/s “…the derived velocities are of the same order as that of prominence material…”

Payne-Scott, Yabsley & Bolton 1947, Nature 260, 256

5.0 x108

1.2 x108

0.4 x108

Plasma density (cm-3)

750 km/s

500 km/s

-Classified as type II radio bursts (Wild & McCready 1950) -Caused by ~10 keV electrons accelerated in MHD shocks (Uchida 1960) -Plasma emission mechanism (Ginzburg & Zhelezniakov 1958) Nelson & Melrose (1985)

WATTSM

ETRE-2(M

EGACYCLE/SEC) -1

Shocks in the IP medium 1953: Gold proposed Interplanetary shock to explain the Sudden Commencement

T. Gold (1920 – 2004)

1962: “Idealized configuration in space, showing solar plasma cloud, the drawn-out field and the shock wave ahead”

MHDshocktheory:deHoffmann&Teller1950Parkerappliedittointerplanetaryshocksin1963

GoldmagneLcbojle

Radio Bursts: Nonthermal Electrons from the Sun Type III (electron beams) v ~ 0.3 c Type II (shocks) v >/~ 600 km/s

Fundamental

Harmonic

f

t

df/dt=df/dr.dr/dt=(V/2)fn-1(dn/dr)V=2L(dlnf/dt)f~n1/2(plasmafrequency)

df/dt~0.1MHz/s

DynamicSpectrummin

UN/ESA/NASA/JAXA Workshop

Range of Phenomena: 2005 May 13 CME

shock

SourceLocaLonN11E12

HaloCME

SEP

SWShock

TypeIIBurst

1689km/sESP100!3000pfu

Sun Earth33h

SSC

in-situ“view”oftheCME

“We suggest that energetic protons are accelerated in the shock front just ahead of the expanding loop structures observed as mass ejections”

Kahler, Hildner, & Van Hollebeke (1978)

Studied 16 Skylab CMEs; 14 had SEP events Found correlation between CME speed and SEP intensity

Skylab CME on January 15, 1974

Cliveretal.1982forGLEs;Caneetal.1988;Reames1990

S.W.Kahler

Interplanetary Shock and Radio Burst

Caneetal.1987;Reineretal.1997;Bougeretetal.1998;Gopalswamyetal.2001;2004;2005,2011

Properties of CMEs Producing SEPs

• Needtobefastenoughtodriveashock

•  TheshockshouldbemagneLcallyconnectedtotheobserver

SEP Intensity vs. CME Speed

SEPIntensitycorrelatedwithCMEspeedLargeScajerSourceandEnvironmentalfactorsconnecLvity

SEP Intensity and Fluence

SEP Intensity and Fluence

>10MeV

Properties of CMEs producing Large SEP Events

•  SEPEventsarecausedbyfastandwide(energeLcCMEs)•  TypicalenergyoftheseCMEs~1032erg•  Shock-drivingcapabilityofCMEskeyforSEPs

CMEs Associated with Type II Bursts and SEPs

SourcesofCMEsassociatedwithtypeIIburstsatf<14MHz(Decameter-hectometerandlongerwavelengths)

TypeIIburstsfromthewesternhemispherearelikelytobeassociatedSEPsduetobejermagneLcconnecLvity

TypeIIburstsfromtheeasternhemisphereareassociatedwithSEPsthatdonotarriveatEarth(e.g.,STEREOB)

Gopalswamyetal.2008AnnGeo

Steaming-limited Intensities of SEP Events

•  Plateauinlowerenergiesa{eriniLalrise•  TensofMeVprotonscauseAlfvenwaves,whichthrojlethe

lowerenergyparLcles(protons,He,Fe,O)

Maxintensity~400Hper(cm2ssr)intheenergyrange5-20MeV

Reames&Ing2010

It Matters Where the Shocks Form FluenceSpectrum

Hard Spectrum Events are more hazardous

Reames2013

Two mechanisms of particle acceleration

• Confinedflares:ParLcleacceleraLoninflares

• CMEsassociatedwithfilamenterupLonoutsideAcLveregions:parLcleacceleraLoninshocks;ESPevents

Confined Flare: No mass motion

Flare X1.5

UniversalTimeNometricradiobursts

NoIPradioemission

•  Microwaveburst,X-rays!nonthermalelectronspropagaLngtowardtheSun

•  Nometricradiobursts!noelectronsawayfromtheSun•  NoInterplanetaryradioemission•  NoSEPevent

Eruptive Flare: CME involved

X1.5

EUVWAVE

Flare

CME

Shock

UniversalTime

TypeIIITypeIITypeIV

•  Radiobursts!nonthermalelectronspropagaLngawayfromtheSun

•  X-rayemission!electronspropagaLngtowardtheSun

•  InterplanetarytypeII•  LargeSEPevent

2007 July 5 IAGA ASIV034

A Generic CME

flux rope

Current sheet

Post-Eruption Arcade (Flare loops)

γ,X-rays,n

IV,µ

Solar wind

p,… e

ep

II

Gopalswamy2006adaptedfromMartens&Kuin1989

impulsiveeventsassociatedwithjets

Solar Cycle Variation

Why Low VBz? Anomalous Expansion of CMEs in Cycle 24

SlopeissignificantlydifferentForagivenspeed,cycle24CMEsarewider

Halos

23

24Cycle-24CMEsare50%widerforV=1000km/s

Pt24

Pt23

Pt23>Pt24

Solar Energetic Particles

SEPs Cycle23* Cycle24 RaBo

>10MeV 81(0.73/SSN)

42(0.67/SSN)

0.52

>500MeV 27(0.24/SSN)

9(0.14/SSN)

0.33

>700MeV(GLE)

13(0.12/SSN)

2(0.03/SSN)

0.15

•  Low-energySEPeventsdrop(48%)~toSSN•  >500MeVSEPeventsdroppedby67%•  >700MeVSEPsdroppedby85%•  Thesecannotbeexplainedbythe34%dropinFWCMEs

>10MeVSEPevents

State of the Heliosphere

Gopalswamyetal.2014GRL(updated)

24%

19%

•  ReducedB•  ReducedacceleraLonefficiency(Kirk,1994)dE/dt∝B(rateofenergygain)

•  ReducedAlfvenspeednearSun! NomajorreducLoninthe#SEPEvents

Parameter SC23 SC24 %Decline

Pt(pPa) 43.1 32.6 24

B(nT) 6.7 5.40 19

N(cm^-3) 6.5 6.0 8

T(x10^5K) 1.1 0.8 28

Va(km/s) 58.2 48.0 18

8%

28%

18%

SWx Sources: Cycle 24 Compared to Previous Cycles

22

24

•  SWxinCycle24isclearlyverymild•  CMEandsunspotacLvityhavediscordantbehaviorbetweenthetwosunspotnumberpeaks•  MorefastCMEsduringfirstpeak,butasmallerSSN•  X-classflaresaremoreduringthesecondpeak•  #ofSEPevents,magneLcstormssimilartoCMEs

2321

Extreme SEP Events

>10MeV

Miyakeetal.2012;Mekhaldietal.2015

Back up Slides

Extreme SEP Events

Notes

• Atomicmassunit(amu)=1/12themassof12C•  Itiscloseenoughtonucleonmasses• MeVpernucleoninindisLnguishablefromMeVperamuforSEPstudies

•  TotalenergyW=AMuγ;Mu=muc2=931.494MeV•  γ=(1-β2)-1/2;β=v/c• KineLcenergyƐ=AMu(γ-1)

3He-Rich Events Flare-acceleratedparBclesat1AU

3He/4He>0.1(solarwind5x10-4)

NoCMEassociaBonwith3He-richevents

3He-richeventsassociatedwithtypeIIIradioburstsproducebyflare-acceleratedelectronsescapingintotheIPspace

OtherheavyionsandtheFe/O-raBoenhanced

EnhancementsofotherheavyionsandFe/Ouncorrelatedwith3He/4He

Masonetal.1986

Masonetal.1986

Shock Acceleration • 

Decker1988θBNistheanglebetweentheshocknormalandthedirec6onoftheupstreammagne6cfield