1 * Pulsar V=5-50 AU/yr CNM How do we observe AU-scale structure? Pulsars, and optical depth imaging against extended radio continuum sources…. Epoch 1Epoch 2

2 Equivalent width variations  EW = 0 within 2  for: 0823, 1133,1737, 2016  EW  0 for 1929 TSAS: L=5-50AU, n~10 4 cm -4, P~10 6 cm -3 K Stanimirovic, Weisberg et al. (2010)

3 PSR at ~330pc * Welsh et al. (2010) Distance=350 pc, closest in the sample ½ of LOS inside the Local Bubble. HD and HD show NaI absorption as similar velocity  TSAS is within the LB! LOS to B pierces the LB wall for pc. Many diffuse clouds in this direction (Aquila Rift) condensing out of the LB wall or ablated nearby molecular gas TSAS Tspin = K CNM/WNM ratio = only 7%  TSAS properties/production influenced by the history/evolution of the Local Bubble What’s going on with B ?

4 With different sources, essentially continuous coverage. No observed power-law turbulent spectrum on scales: 1 to ~1000 AU. Kendall’s tau test for censored data: P(no correlation) ~60% Inhomogeneity in Galactic distribution of TSAS + v.f.f.<~1% TSAS is not pervasive. If TSAS is tracing the end-scales of turbulence then turbulence may dissipate in bursts or active pockets, or it dissipates very fast. Does the power spectrum extend down to AU- scales? Low optical depth High optical depth * : interferometric other: pulsars

5 With different sources, essentially continuous coverage. No observed power-law turbulent spectrum on scales: 1 to ~1000 AU. Kendall’s tau test for censored data: P(no correlation) ~60% Inhomogeneity in Galactic distribution of TSAS + v.f.f.<~1% TSAS is not pervasive. If TSAS is tracing the end-scales of turbulence then turbulence may dissipate in bursts or active pockets, or it dissipates very fast. Does the power spectrum extend down to AU- scales? * : interferometric other: pulsars