Whistler waves that can produce anomalous resistivity by affecting electrons' motion have been suggested as one of the mechanisms responsible for magnetic reconnection in the electron diffusion region (EDR). Such type of waves, however, has rarely been observed inside the EDR so far. In this study, we report such an observation by Magnetospheric Multiscale (MMS) mission. We find large‐amplitude whistler waves propagating away from the X line with a very small wave‐normal angle. These waves are probably generated by the perpendicular temperature anisotropy of the ~300 eV electrons inside the EDR, according to our analysis of dispersion relation and cyclotron resonance condition; they significantly affect the electron‐scale dynamics of magnetic reconnection and thus support previous simulations.

The anisotropy of solar wind turbulence is a critical issue in understanding the physics of energy transfer between scales and energy conversion between fields and particles in the heliosphere. Using the measurement of Parker Solar Probe (PSP), we present an observation of the anisotropy at kinetic scales in the slow, Alfvénic, solar wind in the inner heliosphere. The magnetic compressibility behaves as expected for kinetic Alfvénic turbulence below the ion scale. A steepened transition range is found between the inertial and kinetic ranges in all directions with respect to the local background magnetic field direction. The anisotropy of k _⊥ ≫ k _∥ is found evident in both transition and kinetic ranges, with the power anisotropy P _⊥/P _∥ > 10 in the kinetic range leading over that in the transition range and being stronger than that at 1 au. The spectral index varies from α _t∥ = −5.7 ± 1.0 to α _t⊥ = −3.7 ± 0.3 in the transition range and α _k∥ = −3.12 ± 0.22 to α _k⊥ = −2.57 ± 0.09 in the kinetic range. The corresponding wavevector anisotropy has the scaling of k ∥ ∼ k ⊥ 0.71 ± 0.17 in the transition range, and changes to k ∥ ∼ k ⊥ 0.38 ± 0.09 in the kinetic range, consistent with the kinetic Alfvénic turbulence at sub-ion scales.

With high‐resolution data of the recently launched Magnetospheric Multiscale mission, we report a magnetic reconnection event at the dayside magnetopause. This reconnection event, having a density asymmetry N_high/N_low ≈ 2 on the two sides of the reconnecting current sheet and a guide field B_g ≈ 0.4B₀ in the “out‐of‐plane” direction, exhibit all the two‐fluid features: Alfvenic plasma jets in the outflow region, bipolar Hall electric fields toward the current sheet center, quadrupolar Hall magnetic fields in the “out‐of‐plane” direction, and the corresponding Hall currents. Obviously, the density asymmetry N_high/N_low ≈ 2 and the guide field B_g ≈ 0.4B₀ are not sufficient to dismiss the quadrupolar pattern of Hall reconnection. This is different from previous simulations, where the bipolar pattern of Hall reconnection was suggested.

The energy of turbulence in the universe, which cascades from large fluid scales to small kinetic scales, is believed to be dissipated through conversion to thermal or nonthermal kinetic energy. However, identifying the dissipation processes and measuring the dissipation rate in turbulence remain challenging. Based on unprecedented high-quality measurements of space plasma turbulence by the Magnetospheric Multiscale mission, we propose a novel approach to measure the scale-dependent spectrum of the energy conversion rate between the fluctuating electromagnetic energy and plasma kinetic energy. The energy conversion rate spectrum is found to show a positive bulge around the ion kinetic scale, which clearly indicates the dissipation of the turbulent energy. The energy dissipation rate around the ion scale is estimated to be 0.5 × 10⁶ J kg⁻¹ s⁻¹. This work provides basic information on local dissipation in magnetosheath turbulence and sets up a new paradigm for studying the dissipation of universal plasma turbulence.

Traditionally, the magnetotail flow burst outside the diffusion region is known to carry ions and electrons together (V_i = V_e), with the frozen‐in condition well satisfied (E + V_e × B = 0). Such picture, however, may not be true, based on our analyses of the high‐resolution MMS (Magnetospheric Multiscale mission) data. We find that inside the flow burst the electrons and ions can be decoupled (V_e ≠ V_i), with the electron speed 5 times larger than the ion speed. Such super‐Alfvenic electron jet, having scale of 10 d_i (ion inertial length) in X_GSM direction, is associated with electron demagnetization (E + V_e × B ≠ 0), electron agyrotropy (crescent distribution), and O‐line magnetic topology but not associated with the flow reversal and X‐line topology; it can cause strong energy dissipation and electron heating. We quantitatively analyze the dissipation and find that it is primarily attributed to lower hybrid drift waves. These results emphasize the non‐MHD (magnetohydrodynamics) behaviors of magnetotail flow bursts and the role of lower hybrid drift waves in dissipating energies.