Li-Jen Chen
Magnetic reconnection is a ubiquitous plasma phenomenon that plays a critical role in particle heating and energization. During reconnection, the topology of magnetic field rearranges, depositing energy into the surrounding plasma through…
Autonomous systems that build structures from natural-language instructions need reliable spatial reasoning, yet large language models (LLMs) make systematic coordinate errors when generating three-dimensional block placements. We present a…
It is a widely accepted paradigm that collisionless magnetic reconnection proceeds at a universal fast rate of $\sim0.1$ when normalized to a properly defined reconnecting magnetic field and Alfv\'en speed, effectively independent of the…
We report the properties of electron distributions and turbulence during a Coronal Mass Ejection (CME) in April 2023 observed by Magnetospheric Multiscale (MMS). The CME exhibits a clear sheath and magnetic cloud (MC), and within the MC,…
The magnetic cloud (MC) of the Coronal Mass Ejection on April 24, 2023, contains sub-Alfv\'{e}nic solar wind, transforming Earth's magnetosphere from conventional bow-shock magnetotail configuration to Alfv\'{e}n wings. Utilizing…
We present a comprehensive study of Magnetospheric Multiscale (MMS) spacecraft encounter with KHI during a geomagnetic storm, focusing on elucidating key turbulence properties and reconnection signatures observed at the edges of KH…
Large-amplitude electrostatic fluctuations are routinely observed by spacecraft upon traversal of collisionless shocks in the heliosphere. Kinetic simulations of shocks have struggled to reproduce the amplitude of such fluctuations,…
An interplanetary shock driven by a coronal mass ejection (CME) containing an interval of sub-Alfv\'enic flow impacted Earth on April 23, 2024. In this article, we analyze the turbulence in the sheath region between the shock and CME to…
When sub-Alfv\'enic (Alfv\'en Mach number MA < 1) plasmas impact Earth, Alfv\'en wings (AWs) develop. A Multiscale Atmosphere Geospace Environment (MAGE) simulation of the April 2023 storm, validated by Active Magnetosphere and Planetary…
Using Mars Atmosphere and Volatile EvolutioN Magnetometer observations, we report the first statistical study of ultra-low frequency (ULF) waves at the Martian foreshock. The analyzed foreshock ULF wave events are observed in the…
We report Magnetospheric Multiscale observations of oxygen ions (O+) during a coronal mass ejection in April 2023 when the solar wind was sub-Alfv\'enic and Alfv\'en wings formed. For the first time, O+ characteristics are studied at the…
The magnetic cloud within an interplanetary coronal mass ejection (ICME) is characterized by high magnetic field intensities. In this study, we investigate the interaction of a magnetic cloud carrying a density structure with the Earth's…
Magnetic reconnection changes the magnetic field topology and facilitates the energy and particle exchange at magnetospheric boundaries such as the Earth's magnetopause. The flow shear perpendicular to the reconnecting plane prevails at the…
Simulations have played a critical role in the advancement of our knowledge of magnetic reconnection. However, due to the inherently multiscale nature of reconnection, it is impossible to simulate all physics at all scales. For this reason,…
We report a rare regime of Earth's magnetosphere interaction with sub-Alfv\'enic solar wind in which the windsock-like magnetosphere transforms into one with Alfv\'en wings. In the magnetic cloud of a Coronal Mass Ejection (CME) on April…
Collisionless shocks are ubiquitous structures throughout the universe. Shock waves in space and astrophysical plasmas convert the energy of a fast-flowing plasma to other forms of energy, including thermal and magnetic energies. Plasma…
On April 24th, 2023, a CME event caused the solar wind to become sub-Alfvenic, leading to the development of an Alfven Wing configuration in the Earth's Magnetosphere. Alfven Wings have previously been observed as cavities of low flow in…
In the vicinity of Earth's orbit, the typical solar wind Alfv\'{e}n Mach number exceeds 5, and the super-Alfv\'{e}nic solar wind drives a conventional magnetosphere configuration. However, at the ejecta phase of an interplanetary coronal…
Lunar crustal magnetic anomalies (LCMA) are sub-ion-gyroradius structures that have been shown to stand off the solar wind (SW) plasma from the Moon's surface, forming shock-like discontinuities and reflecting incident SW protons. In this…
Collisionless shock waves are one of the main forms of energy conversion in space plasmas. They can directly or indirectly drive other universal plasma processes such as magnetic reconnection, turbulence, particle acceleration and wave…