Michael Brown Swarthmore College, NSF Center for Magnetic Self-Organization Tim Gray, Ed Dewey ’10, Bevan Gerber-Siff ’10, Kevin Labe ‘11 Vernon Chaplin ’07, Lake Bookman `08 M. J. Schaffer E. V. Belova Research supported by US DOE and NSF Outflow jets, ion heating, and 3D structure in SSX

CMSO activities on SSX 3D Reconnection, flow, heating (T i, T e ) Mach probe collaboration with MST Simulation collaboration with UW Student training: 16 honors students PhD plasma programs at Princeton, Wisconsin Berkeley, Caltech, MIT, Michigan, UCLA Postdoc support (Tim Gray, Chris Cothran)

SSX parameters

Spheromak formation

2D MHD simulation

Tangled 3D magnetic lines (lab and solar) one foot tall 5 earth diameters tall

Electron Diffusion Region Reconnection geometry (2D model) Separa trix Inflow (slow) Outflow (fast, Alfvenic) Current flow (out) Electron flow (in)

3D hybrid simulation (Y. Lin) Kinetic ions (5x10 8 ions), fluid electrons

Simulation results: 3D resistive MHD (E. Belova, PPPL)

Stills from 3D simulation

SSX device (distributed probe array) Opposing magnetized plasma guns Close fitting copper flux conserver Midplane IDS access for flow studies

Local 3D probe measurements Right-handed Spheromak Left-handed spheromak Reconnected poloidal flux

Merging studies in prolate geometry ( ) 0.4 meter diameter, 0.6 meter length reconnection at midplane formation of prolate FRC object ultimately unstable with slow growth rate

Counter-helicity merging (prolate)

3D probe measurements in SSX

Stills from 3D simulation

Bi-directional outflows in SSX High resolution ion Doppler spectroscopy (Cothran, et al, PRL to be submitted J. Fung thesis ‘06)

Ion Doppler Spectroscopy (1.33m)

Ion Doppler spectrometer layout

IDS line shapes (high resolution)

Observation of bi-directional outflow Data is effectively f(v_r)… one pixel is 10 km/s

Stills from IDS movie Dynamics of the flow (bursts, turbulence) encoded in the lineshape

Bi-directional outflows on the sun D. Innes (SOHO SUMER chromosphere) Innes, Nature, 1997 Innes, Solar Physics, 1997

Location of SUMER slit on solar disk SiIV light dispersed along slit

Velocity resolution 10 km/s Spatial resolution 1000 km Spatially localized events

Hot ions in SSX Cothran, et al (SSX) (low density discharges, after glow discharge conditioning, short gas delay)

Hot ions in SSX (merging)

IDS hot ion temperature measurement (one shot, density)

IDS hot ion flow measurement

IDS hot ion temperature measurement (average, 5x10 14 density)

Scaling of T i with density

Scaling of T i with density (single sph) Dipole-trapped, Gaussian fit, early in formation (30-40  s)

IDS ion temperature measurement HeII nm (T He > T C )

Te from CIII (97.7 nm) to CIV (155 nm) ratio

T e from CIII (97.7 nm) to CIV (155 nm) ratio (single spheromak)

T e from SXR array fitting Observe electron heating with SXR during  s reconnection period

Hot ions in the extended corona Cranmer, Space Science Rev, 2002 (UVCS)

UVCS line of sight

SSX density SSX Alfven speed SSX magnetic field Solar wind parameters

Greater than mass ratio ion temperatures

Quadrupole measurement in SSX Mattheaus, et al, GRL (2005) Landreman, (2003) Cothran, et al, GRL (2003)

Driven magnetic reconnection experiments Cothran et al GRL 30, 1213 (2003) Brown et al ApJL 577, 63 (2002) Brown et al Phys. Plasmas 9, 2077 (2002) Brown et al Phys. Plasmas 6, 1717 (1999) Kornack et al Phys. Rev. E 58, R36 (1998) Magnetic probe array RGEAs Large slots cut into FC rear walls define the reconnection region 3D magnetic structure Energetic particles

3D magnetic probe array 600 coils, 5  5  8 array ~2 cm spacing 25 three channel 8:1 multiplexer/integrator boards 10 eight channel 8-bit CAMAC digitizers Full probe readout every 0.8  s

Quadrupole out-of-plane field Ion inertial scale 2 cm

Trajectory of Polar spacecraft Path of tiny Polar

Trajectory of POLAR spacecraft Polar trajectory Mozer, et al, PRL (2002)

POLAR SUB-SOLAR OBSERVATION OF THE ION SCALE

Merging studies in oblate geometry ( ) 0.5 meter diameter, 0.4 meter length turbulent merging process formation of oblate FRC object (sometimes) Ti higher, Te lower than prolate often unstable with Alfvenic growth rate

Trapezoidal flux conserver in SSX

FRC equilibrium with trapezoidal FC

First data from oblate flux geometry

FRC equilibrium with trapezoidal FC

2D merging simulation (N. Murphy)

Equilibrium with trapezoidal FC

Coming up (summer 2008)… Search for hot ions (O, N, …) … will need amplifiers (32 ch) and/or doping

New high resolution mag probe (will need amplifiers… 48 channels)

New high resolution prototype mag probe (1 mm resolution, 2 axis)

Btheta Radial distance (cm) Microsecond fluctuations at the mm scale

Trapezoidal flux conserver in SSX

Stable Oblate FRC in SSX (sometimes)

T i and T e in oblate merging in SSX T i higher, T e lower than prolate

Density at midplane with merging

Dynamic merging events in SSX Unstable! Turbulent?

Spheromaks in SSX

Trapezoidal flux conserver in SSX

Summary (1) Bi-directional sub-Alfvenic outflow measured with ion Doppler spectroscopy on SSX Hot ions and warm electrons also observed in the laboratory using spectroscopy/soft x-rays

Summary (2) Measurement of Ti for different ion mass (Carbon, Helium, Silicon) Electron heating observed during merging events using soft x-ray array… less heating for single spheromak

Summary (3) 3D structure measured at the ion inertial scale in SSX merging experiments First laboratory measurement of out of plane quadrupole field observed on length scale similar to Polar observations at the magnetopause

Summary (prolate) Bi-directional sub-Alfvenic outflow measured with ion Doppler spectroscopy on SSX Both ions/electrons heated by reconnection Spheromak merging creates unstable prolate FRC object with reconnection at midplane

Summary (oblate) Merging in oblate geometry in SSX Hot ions and warm electrons also observed in the laboratory using spectroscopy/soft x-rays

Summary (2) Mach probe measurements corroborate IDS flow results during merging events Electron heating observed during merging events… less heating for single spheromak

Future studies (fall 2008) Measurement of Ti for different ion mass (Carbon, Helium, Xenon) Continue search for stable merging in oblate geometry

Future studies (fall 2008) High resolution, high frequency mag probe (Tobin Munsat collaboration) Mach and retarding grid ion probes