Heliospheric physics by plan‐AHiroaki Isobe (Kyoto Univ)
Contribu<on from: S. Imada (JAXA), R. Kataoka (Tokyo Tech.),H. Miyahara (Univ. Tokyo), H. Hara, M. Shimojo (NAOJ)• Heliospheric imager and in‐situ measurements have been in“op<on” list for plan‐A. LiPle discussion so far, though.

• Heliospheric imager• Cosmic ray

Heliospheric imaging

by bringing STEREO/HI‐like imager to high la<tude

Interplanetary Coronal Mass Ejec<ons (iCME) and Corota<ng Interac<on Region (CIR)
have been imaged by STEREO/Heliospheric Imager (HI)Top‐view diﬀerent from side‐view
Reames 1999

CIR can be imaged by~6hour exposure(Hara‐san’s talk)•CME‐CIR interac<on•Magne<c connec<on of Earth and CME

Combina<on with in‐situ observa<onBothmer & Schwenn 1993

Iden<ﬁca<on of low‐corona and on‐disk
counterpart ofinterplanetary CME

Rouillard+09

Solar energe<c par<cles (SEP)

Heliospheric imaging

Proton ﬂux (GOES)

Earth3D MHD simula<on
Kataoka+ 09• Combining the heliospheric imaging
and in‐situ observa<on will enable tostudy:‐ CME‐earth magne<c connec<vity‐ dependence of SEP accelera<on onCME speed and shock angle etc.

Cross‐scale observa<on of space plasma• Ion iner<a length 100~1000 km in solar wind
• STEREO/HI 2’s pixel size 70”... 50000km/pix for 1AU• Scale gap not desperately huge
• Cross‐scale observa<on from global MHD to kine<c scales in spaceplasma is most likely to happen by heliospheric imaging (+ in‐situ).
• Solar wind speed ~400km/s. Exposure should be <30 s to resolve
10000km. Need 3‐4 orders of magnitude increase in sensi<vity fromSTEREO/HI...

Out‐of‐eclip<c observa<on of cosmic rays (CR)
McDonald 98• Data available from
Voyager1 (<40°),
Voyager2 (<30°),
Pioneer 11 (<20°),
Ulysses (>80°)

V1V2
P11P12

Ulysses orbit

Ulysses result• CR intensity increases ~30%
from eclip<c to high la<tude,
despite the theore<cal
predic<on of factor >10
increase• Challenge to transport theory.
• More data deﬁnitely necessary
to see the la<tudinal gradientas a func<on of 11‐ and 22‐
cycle• Fast, con<nuous, and long‐term la<tudinal scans by plan‐Awill be of great advantage

2013~

Now

Duldig 2000

Anomalous Cosmic Ray• 1‐100Mev/nucleon• Origin has been believed
to be pick‐up ionsaccelerated by theheliospheric termina<onshock• Prove for local interstellar
medium (LISM)

Voyager observa<ons of termina<on shock
Stone et al. 2008, Nature
V1’s TS
V2’s TS2005

2006

2007

• ACR intensity doesn’t peak at TS
by keeps increasing monotonically• Inconsistent with theore<calpredic<on of shock accelera<on2008 • Accelera<on by magne<creconnec<on in heliosphericcurrent sheet? (Lazarian & Opher
2009, Drake et al. 2010)•Similar to pulsar wind
• Diﬀerent la<tudinal /longitudinal
dependence from TS?

Probing local interstellar medium (LISM)•Interstellar Boundary Explorer(IBEX) obtained all‐sky map ofEnerge<c Neutral Atoms (ENA).
•ENAs are (believed to be) pick‐up
ions that are heated (~1keV) neartermina<on shock and thenexchange the charge withsurrounding plasma• Strange ribbon‐like structure
found... eﬀect of interstellar B?
McComas+ 2009, ScienceCR and dynamo
cycle period

grand maxima

Grand mimina• GCR‐origin isotopes (C14, Be10 etc) are the most direct proxyfor long‐term (>400 year) solar ac<vity and cyclic behavior
during grand minima• Understanding and precise modeling of CR transport inheliosphere is essen<ally important to reconstruct the pastsolar ac<vity from isotope recodesRequired instrument and trajectory• Ulysses/COSPIN.... 5kg/detector• Measurements of solar wind plasma and magne<c ﬁeld aredesired. Jupiter op<on preferred.
• Higher is bePer, but >40° allows measurement outside the<lted heliospheric current sheet• Data rate negligible• Synergy with other projects‐ Solar Orbiter / Energe<cPar<cle Detector (EPD)‐ ISS / Calorimetoric Electron
Telescope (CALET, 2014~)

Summary• Heliospheric imager– Ul<mate observa<on for space weather– only prac<cal possibility to directly observe from global
MHD to kine<c scales in space/astrophysical plasmas• Cosmic ray measurement– s<ll too liPle data... any new informa<on, par<cularly
la<tudinal dependence, useful to improve the CR
produc<on and modula<on models– reconstruc<on past solar ac<vity from CR‐related isotopes=> Dynamo

Personal view
• If we go for plan A, HI and CR could have priority overcoronal observa<on– polar corona already seen from side
– jets, waves and fast wind... can be studied in disk coronalhole• They are not the op<on for “someone”. There are young
Japanese scien<sts (incl. myself) who are willing to do
this