Linking Interplanetary Coronal Mass Ejections (ICMEs) observed in-situ to their CME origin at the Sun

SHINE Student Day tutorial

July 29th 2018

Yeimy Rivera

University of Michigan

Overview

• Tutorial: CMEs – Remote sensing

observation of CMEs

– Dynamics and Evolution

– In-situ signatures

• Research: Compositional signatures to derive the thermal history

Yeimy Rivera | Linking ICMEs observed in-situ to their CME origin at the Sun | 2

Yeimy Rivera | Linking ICMEs observed in-situ to their CME origin at the Sun | 3

• CMEs are large eruptions at the Sun that propel massive amounts of ionized material into the Interplanetary Medium

• Three-part structure of CMEs – Leading edge and cavity: n=107-8 cm-3 and T > 106 K

– Prominence (Core): n = 109 -11 cm-3 and T =104-5 K (Occurring 70% of the time)

LASCO/SOHO C2 white light image, FOV 1.5-6 Rs

Coronal Mass Ejections

SDO/AIA 171Å band (log T = 5.8), 193Å band (log T = 6.1) taken from Parenti et al. (2012)

CME Dynamics

• Acceleration/Deceleration – MHD form of 'aerodynamic' drag

imposed by solar wind is significant factor to CME propagation and transit time (Vršnak and Žic 2007, Gopalswamy et al. 2001)

• Expansion – More radial in the inner corona and

self-similar out in the Heliosphere (Chen 2011)

• Heating – Prominence material is observed to

transition from absorption to emission in EUV images (Landi et al. 2010)

– Heating source is still an open question

Yeimy Rivera | Linking ICMEs observed in-situ to their CME origin at the Sun | 4

LASCO/SOHO C3 white light image, FOV 4 -30 Rs

Series of images for a CME in STEREO-A EUVI-A 284Å line (Fe XV formation temperature of 2x106 K)

taken from Landi et al. (2010)

• Freeze-in process undergone by ions (Hundhausen et al. 1968)

– Rapid decrease in density diminishes the ionization and recombination processes in the plasma

– Ionization level is unchanged beyond the freeze-in height allowing to probe the plasma near the Sun

Ion Freeze-in Process

Yeimy Rivera | Linking ICMEs observed in-situ to their CME origin at the Sun | 5

(Landi et al. 2012)

Yeimy Rivera | Linking ICMEs observed in-situ to their CME origin at the Sun | 6

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Interplanetary CMEs

• Plasma properties

- Low proton density • Magnetic Field

- Flux rope, field rotation

Collection of signatures used to identify ICMEs within the continuous solar wind

Yeimy Rivera | Linking ICMEs observed in-situ to their CME origin at the Sun | 7

Interplanetary CMEs

• Energetic Particles - Counter-streaming

electrons • Forbush effect

- Reduction of cosmic ray flux

Yeimy Rivera | Linking ICMEs observed in-situ to their CME origin at the Sun | 8

Interplanetary CMEs

• Compositional anomalies (as compared to solar wind)

- O7+/O6+ enhancement - Higher average charge

state - Characterized by

period of alpha-to-proton >0.08

Deriving properties of Coronal Mass Ejections (CMEs) using in-situ charge state distributions

Yeimy Rivera1, Enrico Landi1, Sue Lepri 1 and Jason Gilbert1 1University of Michigan

July 29th 2018

Michigan Ionization Code

• The MIC is solves a time-dependent ionization equation that governs the evolution of ions in the plasma as they propagate from the Sun (Landi et al. 2012)

• Main inputs:

– Electron density

– Electron temperature

– Bulk flow

• Assumptions:

– Local Thermodynamic equilibrium at boundary

– Electron velocity Maxwellian distribution

Sources

Sinks

MIC Output

Yeimy Rivera | Deriving properties of CMEs using in-situ ion distributions | 10

Michigan Ionization Code

Χ2 calculation

Vary parameters to adjust input

profiles

Best fit results

MAIN INPUTS 1. Density, temperature

and velocity profiles 2. Parameter ranges

and increment size 3. In-situ relative

abundances for each ion species Search

Algorithm

Search Algorithm

Yeimy Rivera | Deriving properties of CMEs using in-situ ion distributions | 11

Final Distributions

χ2 =0.304, 95% confidence

level

Charge State Charge State

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*Plasma Component (PC)

*

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Plasma Evolution

Yeimy Rivera | Deriving properties of CMEs using in-situ ion distributions | 13

Summary • A combination of ions generated from four plasma components undergoing

distinct thermodynamic evolution effectively reproduced the observed ionic distributions

• Plasma component properties at the Sun are similar to those found in prominences/PCTR also includes a warmer component resembling coronal plasma

Next Steps

• Compare results with heating mechanism – Current sheet dissipation

– Wave heating

Yeimy Rivera | Deriving properties of CMEs using in-situ ion distributions | 14

Heating rate

Thank you!

Yeimy Rivera | Deriving properties of CMEs using in-situ ion distributions | 15

Citations 1. Chen, P F, "Coronal mass ejections: Models and their observational basis", Living

Reviews in Solar Physics 8 (2011).

2. Gopalswamy, Nat and Lara, Alejandro and Yashiro, Seiji and Kaiser, Mike L and Howard,

Russell A, "Predicting the 1-AU arrival times of coronal mass ejections", Journal of

Geophysical Research: Space Physics 106, A12 (2001), pp. 29207--29217.

3. Hundhausen, A. J. and Gilbert, H. E. and S.J., Bame, "Ionization state of the

interplanetary plasma.", Journal of Geophysical Research 73, 13 (1968), pp. 5485--5493.

4. Landi, E and Raymond, J C and Miralles, M P and Hara, H, "Physical Conditions in a

Coronal Mass Ejection from HINODE, STEREO, and SOHO Observations", The

Astrophysical Journal 711, 1 (2010), pp. 75--98.

5. Landi, E. and Gruesbeck, J. R. and Lepri, S. T. and Zurbuchen, T. H., "New Solar Wind

Diagnostic Using Both in Situ and Spectroscopic Measurements", The Astrophysical

Journal 750, 2 (2012), pp. 159.

6. Parenti, S and Schmieder, B and Heinzel, P and Golub, L, "ON THE NATURE OF

PROMINENCE EMISSION OBSERVED BY SDO /AIA", The Astrophysical Journal 754, 1

(2012), pp. 66.

7. Richardson, I G and Cane, H V, "Near-earth interplanetary coronal mass ejections

during solar cycle 23 (1996 - 2009): Catalog and summary of properties", Solar Physics

264, 1 (2010), pp. 189--237.

8. Vršnak, B and Žic, T, "Transit times of interplanetary coronal mass ejections and the

solar wind speed", A&A 472 (2007), pp. 937--943.

SHINE Session:

Insights into CMEs

and Their

Substructure(s)