Hydrogen alpha X-ray, and metric and kilometric radio data to examine the solar sources of energetic 3He-rich particle events observed near earth in association with impulsive 2 to 100 keV electron events were applied. Each 3He/electron event is associated with a kilometric type 3 burst belonging to a family of such bursts characterized by similar interplanetary propagation paths from the same solar active region. The 3He/electron events correlate very well with the interplanetary low frequency radio brightnesses of these events, but progressively worse with signatures from regions closer to the Sun. When H alpha brightnings can be associated with 3He/electron events, they have onsets coinciding to within 1 min of that of the associated metric type 3 burst but are often too small to be reported. The data are consistent with the earlier idea that many type 3 bursts, the 3He/electron events, are due to particle acceleration in the corona, well above the associated H alpha and X-ray flares

Kahler, S. W.

Liggett, M.

Lin, R. P.

Reames, D. V.

Stone, R. G.

English

NASA Technical Reports Server

269 SH 2.2-4
SOLARSOURCEREGIONSOF 3HE-RICHPARTICLEEVENTS
S.W.Kahler
EmmanuelCollege,Boston,Massachusetts02115 USA
R.P. L1n
SpaceSciencesLaboratory,Unlversityof California
Berkeley,Californla 94720 USA
D.V.Reames
Laboratoryfor High EnergyAstrophysics,GoddardSpace FlightCenter
Greenbelt,Maryland 20771 USA
R.G. Stone
Laboratoryfor ExtraterrestrlalPhyslcs,GoddardSpace FllghtCenter
Greenbelt,Maryland 20771 USA
M. Liggett
Big Bear SolarObservatory,CaliforniaInstituteof Technology
Pasadena,Callfornla 91125 USA
ABSTRACT
We use Ha, X-ray,and metricand k11ometrlcradlodatato examlne
the solarsourcesof energetic(~ 1 MeV/nucleon)3He-richparticle
eventsobservednearearth in assoclationwith impulslve2 to 100 keV
electronevents. Each3He/electronevent Is associatedwlth a
kilometrictype Ill burstbelonglngto a falailyof such bursts
characterizedby similarinterplanetarypropagationpathsfrom the
same solaractiveregion. The SHe/electroneventscorrelatevery
wellwith the interplanetarylow frequency(~ 188 kHz) radio
brlghtnessesof theseevents,but progressivelyworsewlth slgnatures
from regionscloserto the Sun. WhenHa brighteningscan be
assoclatedwlth3He/electronevents,they have onsetscoincldingto
within1 mn of thatof the associatedmetrictype Ill burstbut are
oftentoo smallto be reported. The data are consistentwith the
earllerideathatmany type III bursts,and now,by impllcatlon,the
3He/electronevents,are due to partlcleaccelerationIn the corona,
well abovethe assoclatedHa and X-rayflares.
1. Introduction.It is now clearthat 3He-rlchenergeticpartlcleevents
are distinguishedfromthe solarenergeticparticle(SEP)eventsof
greaterfluxesand energiesnot only by theiranomalousHe composltlon,
but alsoby their lackof associatlonwlth metrlctype II bursts_nd
coronalmass ejections(Kahleret al. 1985). A comparlsonof 12 He-
richeventswith impulsive2 to 100 keV electroneventssuggeststhat
3He ionsare impulsivelyacceleratedand In3ectedintointerplanetary
spacealongwlth the electrons(Reameset al. 1985). The low fluxesand
slowspeedsof the E ~ 1MeV/nucleon3He ionsmake injectlontlmes
uncertain,but the closeassociatlonof the particleeventswith fast-
drlfttype Ill radioburstsprovidesthe preclsionof timingneeded
to make the associationof th_ particleeventswith solar phenomena.
69 
S R S E R ONS OF 3 RICH P CLE TS 
.  ahl r 
E anuel ollege, oston, assachusetts 02115 USA 
.   
Space Sciences Laboratory, n1versity of California 
erkeley, aliforn1a 94720 USA 
.  e s 
S  . -  
aboratory for igh Energy strophysics, oddard Space Flight enter 
re lt, ar land 71 S  
.  one 
aboratory for xtraterrestr1al PhYS1CS, oddard pace l1ght enter 
reenbelt, aryland 20771 USA 
. i ett 
Big Bear Solar bservatory, California Institute of Technology 
s dena, al1forn1a 25 S  
TRACT 
We use a, -ray, and etric and k11o etr1c rad10 data to exam1ne 
the solar sources of energetic (~ 1 e /nucleon) 3 e-rich particle 
ts served r rth in ssoc1ation ith 1 ls1ve  to 0 keV 
lectron ts. ch e/ lectron t 1S sociated 1th  
kilometric type III burst belong1ng to a family of such bursts 
characterized by similar interplanetary propagation paths from the 
same solar active region. The 3 e/electron events correlate very 
ell ith the interplanetary low frequency (~ 188 k z) radio 
br1ghtnesses of these events, but progressively orse 1th slgnatures 
from regions closer to the Sun. hen a brightenings can be 
assoc1ated 1th 3 e/electron events, they have onsets coinclding to 
ithin  ln f th t f the ssociated etric type III rst t re 
often too s all to be reported. The data are consistent ith the 
earl1er idea that any type III bursts, and now, by i pllcatlon, the 
e/electron e e ts, are due to art1cle acceleration 1n the c rona, 
ell ove the soclated  nd -ray flares. 
 ntroduction.  s ow ear t rlch rgetic tlcle nts 
are distinguished from the solar energetic particle (SEP) events of 
greater fluxes and energies not only by their anomalous He co posltlon, 
but also by their lack of associat10n wlth metrlc type II bursts and 
coronal ass ejections (Kahler et ale 1985).  co parlson of 12 3 e-
rich events with impulsive 2 to 100 keV electron events suggests that 
3He ions are impulsively accelerated and lnJected lnto interplanetary 
space along w1th the electrons (Reames et ale 1985). The low fluxes and 
slow speeds of the E ~ 1 MeV/nucleon 3He ions ake inJect10n tlmes 
uncertain, but the close associatlon of the particle events ith fast-
drlft type III radio bursts provides the preclsion of timing needed 
to ake the association of the particle events ith solar phenomena. 
https://ntrs.nasa.gov/search.jsp?R=19850026486 2020-03-20T17:02:17+00:00Z
270
SH2.2-4
To learnmore aboutthe sourcesof theseeventswe examinethe
charact_ristlcsof the Ha flaresand type Ill burstsassociatedwlth
the 12 _He-rlcheventsstudledby Reameset al. (1985)
2. Observatlonsand Analysls.The tlmesof the 12 eventsare glven in
Table I_ Severalof theseeventsoccurredon the sameday and In these
casesare assoclatedwlth Ha flaresin the same activereglon. In
eachcasewe glvethe tlme of the onsetand the maximumreportedburst
size of the assoclatedmetrictype Ill radioburst. The approxlmate
flaresltesand McMathreglonnumbers,basedon bothreportedHa
flaresand inspectlonof Ha patrolfllms,are also listed. In three
caseswe glve alternatlvesuspectedMcMathreglonsin parentheses.All
H_ eventswere subflaresexceptfor the November8 IB flare.
Each3He/electroneventwas assoclatedwlth a prominentkilometrictype
III burst observedwlth the Meudon/GSFCsolar radloexperlmenton ISEE-
3. An examlnationof the kilometrlcdata duringthe few hours before
and afterthe type Ill burst revealsthatthat burst is one of a famly
of such bursts,all of whlch shownearlyidenticalsolarelongation
anglesas a functlonof radlofrequency. This suggeststhat the
energeticelectronsproducingthe burststraversesimilarpaths froma
singlesolarreglonthroughthe interplanetarymedlum. Figure1 shows
an exampleof suchburstsdurlnga 6 hr intervalon 1979August14. We
have listedin Table 1 the numberof promlnentkilometrlctype Ill
burstsIn each suchfamilyduringan 18 hr periodaroundthe time of the
3He/electronburst. The lastcolumngivesthe numberof burstsposslbly
assoclatedon the basis of the timlngswlth llstedHa flaresin the
actlvereglonpresumedto be the sourceof the 3He/electronevent.
Numbersin parenthesesare the numbersof burstsposslblyassociated
wlth listedHa flaresIn the alternativeactlvereglonsfor the three
datesfor whlch the activeregionis in some doubt.
TABLE 1
Date Type Ill Approx. H_ McMath Totalkm Totalwith
StartUT Classe Locatlon OnsetUT Re_1on t_pe Ill Ha flares
1978
Nov 8 1751 3GG N18 E12 1751 643 2 2
Nov 27 2056 3GG N26 w47a 2055 672 (673) 6 0 (4)
Dec 26 1319b - $21 w41a,d -- 721")
Dec 26 2122 WNGc $21 w45a 2104 721_ 4 0
1979
Feb 10 1818 3GG N13 w23a < 1800 807 (808) 6 2 (1)
May 17 0558 2G $35 W78a 0551 996.(010)13 3 (0)
Aug 14 1728 3GG $18 W45 1728 205_
Aug 14 2048 3GG $17 W48 2048 205J 4 2
Sept 6 0906 2GG N20 W62 0906 252_
Sept 6 1148 3GG N18 W67 1148 252L
Sept6 1332 3GG : N16 W63 1332 252_ 10 5
Sept 6 1851 2GG _ N16 W65a 1850 252.1.
a flare not listedIn SGD, _ut foundIn visualinspectionof Ha films.
b start time of 1980 kHz burst.
c weak intermittentgroup.
d no conflrmationw_th optlcaldata.
e GG: > 10 type Ill bursts;G: < 10 type I;I bursts.
270 
SH 2.2-4 
To learn more about the sources of these events we examine the 
ch ract3ri st 1 c  of the H a fl ares and type II I bur ts associ ated W1 th the 12 He-r1ch events stud1ed by Reames et ale (1985) 
2. Observat10ns and Analys1s. The t1mes of the 12 vents are glven ln 
Table 1. Several of these events occurred on the same day and 1n these 
cases are assoc1ated w1th Ha flares 1n the same actlve reg10n. In 
each case we glve the t1me of the onset and the maximum reported burst 
size of the aSSOCl ated metri c type I II radi 0 burst. The approxlmate 
flare sltes and cMath reg10n numbers, based on both reported Ha 
flares and inspect10n of Ha patrol f1lms, are also listed. In three 
cases we glve alternat1ve suspected cMath reglons in parentheses. All 
Ha vents w re subflares except for the November 8 IB flare. 
Each 3He/ lectron vent was assoclated wlth a prominent kilometric type 
III burst observed w1th the Meudon/GSF  solar rad10 exper1ment on ISEE-
3. An exam1nation of the kilometr1c data during the few hours before 
and after the type I II burst reveals that that burst 1 s one of a fam1ly 
of such bursts, all of Wh1Ch show nearly identicdl solar elongation 
angles as a funct10n of rad10 frequency. This suggests that the 
energetic electrons producing the bursts traverse simllar paths from a 
single solar reg10n through the 1nterplanetary med1um. Figure 1 shows 
an example of such bursts dur1ng a 6 hr interval on 1 79 A gust 14. We 
have listed 1n Table 1 the number of prom1nent kilometr1c type III 
bursts 1n each such family during an 18 hr period around the time of the 
3He/ lectron burst. The last column gives the number of bursts poss1bly 
assoc1ated on the basis of the tim1ngs w1th llsted Ha flares in the 
act1ve reg10n presumed to be the source of the 3He/electron event. 
Numbers in parentheses are the numbers of bursts poss1bly associated 
w1th listed Ha flares 1n the alternative act1ve reg10ns for the three 
dates for Wh1Ch the active region 1S in some doubt. 
TABLE 1 
Date Type III Approx. Ha cMath Total km Totdl with 
Start UT Classe Locat10n Onset UT Reg10n type I II Ha flares 
1978 
Nov 8 1751 3GG N18 E12 1751 643 2 2 
Nov 27 2056 3GG N26 W47 d 2055 672 (673) 6 0 (4) 
Dec 26 319b S21 W41 a,d 72U Dec 26 122 WNGc S21 W45 a 2104 721 4 0 
1979 
Feb lO 1818 3GG < 1800 807 (808) 6 2 (1) 
May 17 0558 2G 0551 996 (OlO) 13 3 (0) 
Aug 14 1728 3GG 1728 205] Aug 14 2048 3GG 2048 205 4 2 
Sept 6 906 2GG 906 52 
Sept 6 1148 3GG 1148 52 
Sept 6 1332 3GG 1332 52 lO 5 
Se t 6 1851 2GG 52 
fare not listed 1n 
b start time of 1980 kHz burst. 
1n V1sua inspect10n of Ha f1 ms. 
c weak intermittent group. 
d no conf1rmatio  \filth opt1cal d ta. 
e G: > 10 type III bursts; G: < 10 type U I bursts. 
271
SH 2.2-4
90° , , ,
ISEE-3 466 KHZ '60° _W
5d'- A A A B A A B A B
. _oo_C C
E -60" -
-gd
oo
14OI_,E70 I E 76 I E_ W/
LOG TA /
IO o
6O I I I I I
1200 1300 1400 I,_DO 1600 17'00 1800
LITON 14AUGUST 1979
Figure 1. 466 kHz data from 1979 August 14. Three famllies of bursts
labeled A,B, and C were present durlng the 6-hr interval. B events were
associated wlth McMath 205. @is the solar elongation angle; _ a
measure of the source slze, wlth 1 belng a polnt source; and TA the
antenna temperature. Assoclated II_ flare reports are also shown.
In two of the three events wlth questionable actlve reglon assoclatlons
we see that the H_ flare associations of the alternative reglons are
worse than for the preferred actlve reglons, although the statistics are
limlted. Using onlx these data, we could have selected the preferred
reglon for all the _He/electron events except for the November 27 event
and the.two on December 26. In the latter case no cholce could be made.
On the other hand, by slmply look_ng for listed Ha flares at well
connected longitudes, we would have mlsldentlfled the source reglons in
two or three cases.
To get a better Idea of the slgnatures of the 3He/electron events, we
have compared reported Ha flares, metric type III bursts, and antenna
temperatures of the 1980 and 188 kHz bursts for the kllometric bursts
wlth and without 3He/electron events. We omlt the large sample of
events on May 17, few of whlch are assoclated with Ha flares or metrlc
type III bursts. The results are shown In Figure 2. The contrast
between the two groups increases as we consider first the Ha flares
and then the progressively lower frequencles of _he type III bursts. At
188 kHz the logs of TA of all but one of the 12 _He/electron events
exceeded 10.5. On th_ other hand, this value v_as exceeded by only 3 of
the 21 kilometrlc type III burst group.
3. Discussion. Each kllometrlc burst family Is characterlzed by the
degree of its assoclatlon wlth reported metrlc type III bursts and H_
flares as shown In Table I. The famllles of November 8, August 14, and
September 6 are well associated, whlle the others are not. This lack
of observed assoclated Ha actlvlty wlth several 3He/electron events
271 
SH 2.2-4 
9ifr-------.-------~------~------~------~----~ 
w 6if 
3d 
ISEE - 3 
A A 
466 KHZ 
A B 
¢ ~·bd~~~~._~~~~_d~~~~~ 
-300 c 
LOG TA 
60~----__ ~ ______ ~ ______ ~ ______ L_ ______ L_ ____ ~ 
1200 1300 1400 1500 1600 1700 1800 
UT (J\J 14 AUGUST 1979 
Flgure 1. 466 kHz data from 1979 August 14. Three famllies of bursts 
labeled A,B, and C were present durlng the 6-hr lnterval. B events were 
associated wlth McMath 205. • is the solar elongation angle; a a 
measure of the source SlZe, wlth 1 belng a pOlnt source; and TA the 
antenna temperature. Assoclated 11a flare reports are also shown. 
In two of the three events wlth questlonable actlve reglon assoclatlons 
we see that the Ha flare associations of the alternative reglons are 
worse than for the preferred actlve reglons, although the statlstlcs are 
limlted. Using onl~ these data, we could have selected the preferred 
reglon for all the He/electron events except for the November 27 event 
and the.two on December 26. In the latter case no cholce could be made. 
On the other hand, by slmply looklng for listed Ha flares at well 
connected longltudes, we would have mlsldentlfled the source reg10ns 1n 
two or three cases. 
To get a better ldea of the slgnatures of the 3He/electron events, we 
have compared reported Ha flares, metric type III bursts, and antenna 
temperatures of the 1980 and 188 kHz bursts for the kllometric bursts 
wlth and wlthout 3He/electron events. We omlt the large sample of 
events on ~1ay 17, few of WhlCh are assoclated with Ha flares or metnc 
type III bursts. The results are shown ln Figure 2. The contrast 
between the two groups increases as we conslder first the Ha flares 
and then the progressively lower frequencles of ~he type III bursts. At 
188 kHz the logs of TA of all but one of the 12 He/electron events 
exceeded 10.5. On the other hand, th is value vias exceeded by only 3 of 
the 21 kilometrlc type III burst group. 
3. Discusslon. Each k110metrlc burst family lS characterlled by the 
degree of its aSSOc1atlon w1th reported metr1c type III bursts and Ha 
flares as shown ln Table 1. The fa~llles of November 8, August 14, and 
September 6 are well associated, whlle the others are not. This lack 
of observed assoclated Ha actlvlty wlth several 3He/electron events 
272
SH 2.2-4
3HE EVENTS KM ITI ONLY
_uggests a coronal orlgin for the energetlc jl_ ]__
He ions and electrons. Figure I shows 12
that _he correlatlon between the occurrence 9
of a _He/electron event and a solar/inter- N 6
planetary event Increases wlth increasing F--I
distance of the solar/interplanetary event i i
from the sun. Thls suggests that Ha Y N Y N
actlvlty may have llttle to do wlth the REPORTEDH: FLARES
accelerati°n°f tile3He i°nsand electr°ns 1!____
otherthan to reflectIndirectlythe
presenceof the overlylngevent,presumably N
as a resultof the preclpitatlonof some
fractlonof the energlzedpartlclesas
suggested by Kane et el. (1974). Wealso °'_i_' '3GG _1 2' 3GG
founda closecolnci-T_cebetweenonsets REPOR_T METRICTYPEZZZ
of metrlctype III burstsand onsetsof _t L,
associatedHa and X-rayflaressuggestlng i
thatthe initlalactivltyof the SHe/ N 6
electroneventsbeginsin the highcorona. _ _l
Observations of type III emlssion from 3
interplanetaryelectronbeams are compll- o7 9 _ii3 7 9 ili3
cated by factorsinvolvinggenerat10n(L1n LOG _ (1980 KHz)
et al. 1981)and propagationof the bursts,
complex.S°the Sltuatlon may prove to be more N 111 _ __4. Conclusions. Each 3He/electron event Is
assoclated with a k11ometrlc type III burst OB I0 12 14 8 iO 12 14
which appearsas a memberof a famllyof LOG _ (188 KHz}
burstssharingslmilarinterplanetarypro-
pagationpaths. The membersof eachfamlly Figure2. Histogramsof
dlfferfrom eachother in thelrassoclated Ha flares,metrlctype
antennatemperaturesat dlfferentfrequen- Ill burstsand log TA
cies and In theirmetrictype Ill and Hm for kilometmc type Ill
flare assoclatlons.In our studythe best burstswlth and without
empiricalindicationof the occurrenceof a 3He/electronevents.
3He/electronevent provedto be a hlgh
antennatemperatureat 188 kHz. ReportedHa flareobservatlonsare a
poor guideto the occurrenceor orlglnof theseeventsand in some cases
are msleadlng, perhapsbecauseof Inaccuratereporting. The poor
assoclationof the 3He/electroneventswith Ha flaressuggestsa
high coronalorlglnfor at leastsomeof the events.
Acknowledgements. This work was supported at Emmanuel College by AFGL
Contract AF 19628-82 0039, at GSFC/University of Maryland by NASA
grant HGR21-002316, and at the University of Callfornla, Berkeley in
part by NASA grant NAG5-376.
REFERENCES
Kahler,S. et al. 1985,Ap. J., 290, 742.
Kane,S.R., et al. 1974,SolarPhys.,38, 483.
Lin, R.P.,et al. 1981,A_p.J., 251, 364.
Reames,D.V., et al. 1985,A_p.J., in press.
272 
suggests a coronal or1gin for the energet1c 
3He ions and electrons. F1gure 1 shows 
that the corre at1on between the occurrence 
of a 3He/electron event and a solar/inter-
planetary vent 1ncreases ~nth 1ncreasing 
distance of the s lar/interplanetary vent 
from the sun. Th1S suggests that Ha 
act1v1ty may have llttle to do w1th the 
acceleration of the 3He ions and electrons 
other than to reflect 1ndirectly the 
presence of the overlY1ng event, presu ably 
as a result of the prec1pitat1on of some 
fract10n of the en rg1zed p rt1cles as 
suggested by Kane et ale (1974). We also 
found a close c01ncidence between onsets 
of metrlC type III bursts and onsets of 
associat  H  and X-ray flares su gest1  
that the init1al activ1t  of the 3He/ 
electron events begins 1n the high corona. 
Observations of type III em1ssion from 
interpl ary electr  beams are compl1-
cated by factors 1nvolvi  generat  (L1n 
et ale 1981) and propagati n of the bursts, 
so the s 1 tuat lOn may prove to be more 
complex. 
4. Conclus1ons. Each 3He/electron event 1S 
assoc1ated with a k110metrlc type III burst 
which a pears as a member of a fam1ly of 
bursts shari  slmilar inter la etary pro-
pagation paths. The members of each fam1ly 
d1ffer from each other in the1r assoc1ated 
antenna temperat r s at d1ffere t freque -
cies and 1n their metric type III and Ha 
flare assoc1at10ns. In our study the best 
empirical 1ndicati  of the o curr  of a 
3H /electr  event prove  to be a hlgh 
SH 2.2-4 
3 H E EVENTS KM III ONLY 
12 
9 
N 6 
3 
0.......,.."""""'""""" N 
NT~·Ftb 
s; I 2, 3GG s; I 3~' 3GG REPORTi:~ METRIC TYPE III 
I!~ N 6 
3 
o 
7 9 "13 7 9 " 13 
LOG TA (1980 KHz) 
N '~lill ill 
0 8 10 12 14 8 10 12 14 
LOG TA (188 KHz) 
F1gure 2. H1stogra s of 
Ha flares, metr1c type 
III bursts and log TA 
for kilo etr1c type III 
bursts w1th and w1thout 
3He/electron events. 
antenna temperature at 188 kHz. Reported Ha flare observat1ons are a 
p or gU1de to the occurre ce or or191  of these events and 1n some cases 
are m1slead1ng, perhaps because of lnaccurate reporting. The poor 
assoc1ation of the 3He/electron events with Ha flares suggests d 
high coronal or1g1n for at least some of the events. 
Acknowledi ments. Th1S work was supported at E manuel Coll ge by AFGL 
Contract F 19628-82 0039, at GSFC/University of Maryland by NASA 
grant HGR 21-002316, and at the University of Cal1fornla, Berkeley 1n 
part by NASA grant NAG 5-376. 
REFERENCES 
Kahler, S. et al. 1985, Ap. J., 290, 742. 
Kane, S.R., et ale 1974, Solar Phys., 38,483. 
Lin, R.P., et al. 1981, Ap. J., 251, 364. 
Reames, D.V., et ale 1985, Ap. J., in pre s. 


Solar source regions of 3HE-rich particle events

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server