Observations of Solar Jets

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1 Observations of Solar Jets Coronal Jets X-ray and EUV images Davina Innes Transition Region Jets explosive events UV spectra and since IRIS images Active Region jets Coronal hole jets Everywhere about 30,000 at any one time

2 Basic scenario X-ray jet observed by Yohkoh/SXT Explained in terms of emerging bipole in uni-polar coronal field Shibata et al. 1992

3 Active Region EUV/X-ray jets SDO Observations Running difference 211 A image Red Magnetic field Blue -171 A (1 MK) Green A (2 MK) EUV jets with plane-of-sky velocity km/s sunspot waves and jets Produce Solar Energetic Particles 1. Electron spikes Type III radio bursts 2. Up to factor 10 4 increase in 3 He/ 4 He ratio 3. Enhanced Fe/O abundances 4. Enhanced ultra heavy abundances

4 Type III radio bursts The most frequently observed solar radio burst by WAVES/WIND (Freq MHz). Emission drift from high to low frequency. Time (hrs) Estimated distance from the Sun for 13 MHz emission is 2 Rsun It takes about 17s Produced when suprathermal electrons (velocity ~ 0.2 c) travel outward along open magnetic field lines through the corona and interplanetary medium. Electrons excite Langmuir waves at the electron plasma frequency that are converted into radio waves. f ne frequency proportional to square root electron density

5 The acceleration region Radio emission Radio and footpoint simultaneous. EUV jet lags by 30s. Time series along the jets. Innes et al 2011 EUV emission In situ observations - simultaneous electon spikes and radio emission (Klassen, Gomez- Herrero & Heber 2011; Krucker et al 1999) Electron acceleration at onset i.e. before the EUV jet

6 Anomalous abundances In situ observations from Advanced Composition Explorer ACE Larger enhancements as charge/mass deceases except 3 He 3 He ultra heavy vs 3 He enhancements For 20 impulsive flares Low energy SEPs 400 kev/nucleon Mason etal 2004 charge/mass Mechanisms: Wave-particle resonance Details under investigation. What observation distinguish various proposals? Particle Spectra from impulsive C-type flare dj de E γ E<1.4 MeV ; γ=1.2 E>3 MeV/nuc ; γ = 3.5 Mason et al 2002

7 Coronal hole X-ray jets Hinode X-ray images Jet velocity 800 km/s Alfven waves generated by reconnection at the base of the jet Cirtain et al 2007 Science

8 UV jets on limb observed by IRIS UV spectrometer launched about 1 year ago (27 June 2013) Slit Jaw images at 1400 A spatial pixel 0.16 Emission is mainly Si IV in loops and continuum emission at footpoints Loop brightening and separation at time of jet. Part of Si IV jet seems to be falling back probably see cooling material. Reverse color image i.e bright structure are dark Position of spectrometer slit is the vertical white line.

9 Jets on limb observed by IRIS Si IV line profiles Red line is the profile at the position of the red arrow. Cadences; slit jaw 21 s spectrometer 5.2 s Raster step size 0.35 (300 km), exposure time 5.2 s Reverse color image. Position of the slit is the vertical white line

10 Jets observed by IRIS High velocity (200 km/s) blue wing just outside the footpoint

11 Jets observed by IRIS At the footpoint, bright continuum, small red shift (10 km/s)

12 Jets observed by IRIS Above footpoint, bright continuum, high velocity red wing (>100 km/s)

13 Jets observed by IRIS Large blue shift 1 (800 km) higher up. Asymmetric profiles below the jet.

14 Jets observed by IRIS Red shift from loop leg (green arrow) away and 5 s later 0.35 (300 km)

15 Jets observed by IRIS 550 km higher 11s later Jet emission small redshift. Loop top profile is more or less symmetric

16 Jets observed by IRIS red shift

17 Jets observed by IRIS jet emission

18 Jets observed by IRIS jet emission red shift

19 Jet observed by IRIS jet emission blue shift Alternating red and blue shifts along the jet - interpreted as untwisting fields. Could also be mixture of descending and ejected plasma

20 Jets near disk center seen with IRIS 1400 A slit jaw image Black vertical line is position of the spectrometer slit Running difference of 1400 A images. Arrow point to position of jet. High cadence (3.5 s) sit and stare observation Si IV 1402 emission spectra aligned with slit jaw image. Profile is at the position of red arrow

21 IRIS jet near disk center Broad (100 km/s), symmetric profiles, blue shift (25 km/s) Brightening of the loop before jet JET Jet s projected velocity 1000 km/s

22 Bi-Directional flows Same region 1.5 hrs later - no jet but similar broad profiles Loop with approximately symmetric profiles red/blue shifts out to 200 km/s. Non Gaussian profiles with widths typically km/s Alfven speed about 200 km/s. Sound speed at 10 5 K about 30 km/s. Lasts around 5 min

23 Bi-Directional flows Profiles along an active region loop seen towards the limb. SDO EUV 304A (He II) Spectra off the loop slit jaw image at 1400 A -> Si IV Si IV line profiles Series of raster steps. Step size 0.35, exposure time 5.3s

24 Bi-Directional flows Profiles along a loop at disk center Spectra off the loop slit jaw image at 1400 A -> Si IV Si IV line profiles step size 0.35, exposure time 5.3s

25 Bi-Directional flows Profiles along a loop at disk center Spectra along the loop bad pixel Blue shift below loop slit jaw image at 1400 A -> Si IV Si IV line profiles step size 0.35, exposure time 5.3s

26 Bi-Directional flows Profiles along a loop at disk center Spectra along the loop All along loop see broad profiles (60 km/s). line shift changes blue-red from bottom to top d c b a a c b d slit jaw image at 1400 A -> Si IV Si IV line profiles step size 0.35, exposure time 5.3s

27 Bi-Directional flows Profiles along a loop at disk center Spectra along the loop Because close to the limb magnetic field is not obvious. It looks like +ve in the north. +ve field redshift above loop slit jaw image at 1400 A -> Si IV Si IV line profiles step size 0.35, exposure time 5.3s

28 Bi-Directional flows Broad transition region line shifts associated with loop heating and sometimes with jets Tentative Explanations 1. Ions are rotating around the loop axis Ion gyro-motion initialized by footpoint ejection Motion along helical fields Ion wave interaction 2. Ion thermal motion Ion temperature about electron temperature 3. Very rapid back and forth flows

29 Plasma parameters B=10 G, Ni = 1E10 ion temperature (MK) ion collision rate (s -1 ) ion sound speed (km/s) alfven speed (km/s) 220 beta H II Si IV Si IV ion gyroradius (cm) Doppler width (km/s)