A. Koval

Observations of electromagnetic whistler precursors at supercritical interplanetary shocks

] We present observations of electromagnetic precursorwaves, identified as whistler mode waves, at supercriticalinterplanetary shocks using the Wind search coil magneto-meter. The precursors propagate obliquely with respect tothe local magnetic field, shock normal vector, solar windvelocity, and they are not phase standing structures. All areright-hand polarized with respect to the magnetic field(spacecraft frame), and all but one are right-hand polarizedwith respect to the shock normal vector in the normal inci-dence frame. They have rest frame frequencies f

Shocklets, SLAMS, and field‐aligned ion beams in the terrestrial foreshock

We present Wind spacecraft observations of ion distributions showing field-aligned beams (FABs) and large-amplitude magnetic fluctuations composed of a series of shocklets and short large-amplitude magnetic structures (SLAMS). We show that the SLAMS are acting like a local quasi-perpendicular shock reflecting ions to produce the FABs. Previous FAB observations reported the source as the quasi-perpendicular bow shock. The SLAMS exhibit a foot-like magnetic enhancement with a leading magnetosonic whistler train, consistent with previous observations. The FABs are found to have T_b ~ 80-850 eV, V_b/V_sw ~ 1-2, T_{b,perp}/T{b,para} ~ 1-10, and n_b/n_i ~ 0.2-14%. Strong ion and electron heating are observed within the series of shocklets and SLAMS increasing by factors \geq 5 and \geq 3, respectively. Both the core and halo electron components show strong perpendicular heating inside the feature.

Electromagnetic waves and electron anisotropies downstream of supercritical interplanetary shocks

We present waveform observations of electromagnetic lower hybrid and whistler waves with f_ci 1.01. Thus, the whistler mode waves appear to be driven by a heat flux instability and cause perpendicular heating of the halo electrons. The lower hybrid waves show a much weaker correlation between \partialB and normalized heat flux magnitude and are often observed near magnetic field gradients. A third type of event shows fluctuations consistent with a mixture of both lower hybrid and whistler mode waves. These results suggest that whistler waves may indeed be regulating the electron heat flux and the halo temperature anisotropy, which is important for theories and simulations of electron distribution evolution from the sun to the earth.

INNER HELIOSPHERIC EVOLUTION OF A “STEALTH” CME DERIVED FROM MULTI-VIEW IMAGING AND MULTIPOINT IN SITU OBSERVATIONS. I. PROPAGATION TO 1 AU

Coronal mass ejections (CMEs) are the main driver of space weather. Therefore, a precise forecasting of their likely geo-effectiveness relies on an accurate tracking of their morphological and kinematical evolution throughout the interplanetary medium. However, single viewpoint observations require many assumptions to model the development of the features of CMEs. The most common hypotheses were those of radial propagation and self-similar expansion. The use of different viewpoints shows that, at least for some cases, those assumptions are no longer valid. From radial propagation, typical attributes that can now be confirmed to exist are over-expansion and/or rotation along the propagation axis. Understanding the 3D development and evolution of the CME features will help to establish the connection between remote and in situ observations, and hence help forecast space weather. We present an analysis of the morphological and kinematical evolution of a STEREO-B-directed CME on 2009 August 25-27. By means of a comprehensive analysis of remote imaging observations provided by the SOHO, STEREO, and SDO missions, and in situ measurements recorded by Wind, ACE, and MESSENGER, we prove in this paper that the event exhibits signatures of deflection, which are usually associated with changes in the direction of propagation and/or also with rotation. The interaction with other magnetic obstacles could act as a catalyst of deflection or rotation effects. We also propose a method to investigate the change of the CME tilt from the analysis of height-time direct measurements. If this method is validated in further work, it may have important implications for space weather studies because it will allow for inference of the interplanetary counterpart of the CMEs orientation.

Magnetic field turbulence spectra observed by the wind spacecraft

We are presenting a new Wind MFI high time resolution data set covering 1994-2012. The time resolution of the data, normally 92 ms and occasionally 46 and 184 ms, obtained as onboard averages of the 22.7 ms measurements, allows investigation of both the inertial and dissipation ranges of the magnetic field turbulence. Using this data set we have analyzed the magnetic field turbulence spectra of more than 100,000 hourly solar wind intervals and computed the inertial and dissipation range spectral indices. Our initial results indicate that the spectral indices in the solar wind are distributed as −1.67 ± 0.22 in the inertial range and as −2.76 ± 0.72 in the dissipation range. There is a slight negative correlation between the indices and a region of overlapping inertial and dissipation range indices, where the spectral break may completely disappear.